diff --git a/cubism.v1.js b/cubism.v1.js
index 375c35e..8d898f5 100644
--- a/cubism.v1.js
+++ b/cubism.v1.js
@@ -28,42 +28,60 @@ cubism.context = function() {
       start1, stop1, // the start and stop for the next prepare event
       serverDelay = 5e3,
       clientDelay = 5e3,
+      seek = 0,
       event = d3.dispatch("prepare", "beforechange", "change", "focus"),
       scale = context.scale = d3.time.scale().range([0, size]),
       timeout,
       focus;
 
   function update() {
-    var now = Date.now();
-    stop0 = new Date(Math.floor((now - serverDelay - clientDelay) / step) * step);
-    start0 = new Date(stop0 - size * step);
-    stop1 = new Date(Math.floor((now - serverDelay) / step) * step);
-    start1 = new Date(stop1 - size * step);
-    scale.domain([start0, stop0]);
+    if(seek != 0){
+      stop0 = new Date(Math.floor(seek / step) * step);
+      start0 = new Date(stop0 - size * step);
+      stop1 = stop0;
+      start1 = start0;
+      scale.domain([start0, stop0]);
+    } else {
+      var now = Date.now();
+      stop0 = new Date(Math.floor((now - serverDelay - clientDelay) / step) * step);
+      start0 = new Date(stop0 - size * step);
+      stop1 = new Date(Math.floor((now - serverDelay) / step) * step);
+      start1 = new Date(stop1 - size * step);
+      scale.domain([start0, stop0]);
+    }
     return context;
   }
 
   context.start = function() {
-    if (timeout) clearTimeout(timeout);
-    var delay = +stop1 + serverDelay - Date.now();
-
-    // If we're too late for the first prepare event, skip it.
-    if (delay < clientDelay) delay += step;
-
-    timeout = setTimeout(function prepare() {
-      stop1 = new Date(Math.floor((Date.now() - serverDelay) / step) * step);
-      start1 = new Date(stop1 - size * step);
-      event.prepare.call(context, start1, stop1);
-
-      setTimeout(function() {
-        scale.domain([start0 = start1, stop0 = stop1]);
+    if(seek != 0) {
+      event.prepare.call(context, start1, stop1, function(){
         event.beforechange.call(context, start1, stop1);
         event.change.call(context, start1, stop1);
-        event.focus.call(context, focus);
-      }, clientDelay);
-
-      timeout = setTimeout(prepare, step);
-    }, delay);
+        event.focus.call(context, focus);  
+      });
+    } else {
+      // Realtime
+      if (timeout) clearTimeout(timeout);
+      var delay = +stop1 + serverDelay - Date.now();
+
+      // If we're too late for the first prepare event, skip it.
+      if (delay < clientDelay) delay += step;
+
+      timeout = setTimeout(function prepare() {
+        stop1 = new Date(Math.floor((Date.now() - serverDelay) / step) * step);
+        start1 = new Date(stop1 - size * step);
+        event.prepare.call(context, start1, stop1);
+
+        setTimeout(function() {
+          scale.domain([start0 = start1, stop0 = stop1]);
+          event.beforechange.call(context, start1, stop1);
+          event.change.call(context, start1, stop1);
+          event.focus.call(context, focus);
+        }, clientDelay);
+
+        timeout = setTimeout(prepare, step);
+      }, delay);
+    }
     return context;
   };
 
@@ -74,6 +92,14 @@ cubism.context = function() {
 
   timeout = setTimeout(context.start, 10);
 
+  // seek = fixed end time
+  // if seek = 0 moves back to real time
+  context.seek = function(_) {
+    if(!arguments.length) return seek;
+    seek = +_;
+    return update().stop().start();
+  };
+
   // Set or get the step interval in milliseconds.
   // Defaults to ten seconds.
   context.step = function(_) {
@@ -609,25 +635,49 @@ cubism_contextPrototype.metric = function(request, name) {
       fetching;
 
   // Prefetch new data into a temporary array.
-  function prepare(start1, stop) {
-    var steps = Math.min(size, Math.round((start1 - start) / step));
-    if (!steps || fetching) return; // already fetched, or fetching!
-    fetching = true;
-    steps = Math.min(size, steps + cubism_metricOverlap);
-    var start0 = new Date(stop - steps * step);
-    request(start0, stop, step, function(error, data) {
-      fetching = false;
-      if (error) return console.warn(error);
-      var i = isFinite(start) ? Math.round((start0 - start) / step) : 0;
-      for (var j = 0, m = data.length; j < m; ++j) values[j + i] = data[j];
-      event.change.call(metric, start, stop);
-    });
+  function prepare(start1, stop, callback) {
+    if(start1 > start) {
+      var steps = Math.min(size, Math.round((start1 - start) / step));
+      if (!steps || fetching) return; // already fetched, or fetching!
+      fetching = true;
+      steps = Math.min(size, steps + cubism_metricOverlap);
+      var start0 = new Date(stop - steps * step);
+      request(start0, stop, step, function(error, data) {
+        fetching = false;
+        if (error) return console.warn(error);
+        var i = isFinite(start) ? Math.round((start0 - start) / step) : 0;
+        for (var j = 0, m = data.length; j < m; ++j) values[j + i] = data[j];
+        event.change.call(metric, start, stop);
+        if(callback != null) callback();
+      });
+    } else {
+      var steps = Math.min(size, Math.round((start - start1) / step));
+      if (!steps || fetching) return;
+      fetching = true;
+      // Must be seeking backward... don't need to overlap since we are 
+      // not in realtime
+      //steps = Math.min(size, steps + cubism_metricOverlap);
+      var stop0 = new Date(+start1 + steps * step);
+      request(start1, stop0, step, function(error, data) {
+        fetching = false;
+        if(error) return console.warn(error);
+        prevalues = []
+        for (var j = 0, m = data.length; j < m; ++j) prevalues[j] = data[j];
+        values = prevalues.concat(values);
+        event.change.call(metric, start, stop);
+        if(callback != null) callback();
+      });
+    }
   }
 
   // When the context changes, switch to the new data, ready-or-not!
   function beforechange(start1, stop1) {
     if (!isFinite(start)) start = start1;
-    values.splice(0, Math.max(0, Math.min(size, Math.round((start1 - start) / step))));
+
+    if(start1 > start)
+      values.splice(0, Math.max(0, Math.min(size, Math.round((start1 - start) / step))));
+    else
+      values.splice(stop1, Math.max(0, Math.min(size, Math.round((start - start1) / step))));
     start = start1;
     stop = stop1;
   }
@@ -808,17 +858,34 @@ cubism_contextPrototype.horizon = function() {
 
         // if this is an update (with no extent change), copy old values!
         var i0 = 0, max = Math.max(-extent[0], extent[1]);
+        var iEnd = width;
+
         if (this === context) {
           if (max == max_) {
-            i0 = width - cubism_metricOverlap;
-            var dx = (start1 - start) / step;
-            if (dx < width) {
-              var canvas0 = buffer.getContext("2d");
-              canvas0.clearRect(0, 0, width, height);
-              canvas0.drawImage(canvas.canvas, dx, 0, width - dx, height, 0, 0, width - dx, height);
-              canvas.clearRect(0, 0, width, height);
-              canvas.drawImage(canvas0.canvas, 0, 0);
+            if(start1 < start) {
+              // Need to repaint the left side (seeking, not realtime)
+              var dx = (start - start1) / step;
+              iEnd = dx;
+              if(dx < width) {
+                var canvas0 = buffer.getContext("2d");
+                canvas0.clearRect(0, 0, width, height);
+                canvas0.drawImage(canvas.canvas, 0, 0, width - dx, height, dx, 0, width - dx, height);
+                canvas.clearRect(0,0, width, height);
+                canvas.drawImage(canvas0.canvas, 0, 0);
+              }
+            } else {
+              var dx = (start1 - start) / step;
+              i0 = width - dx - cubism_metricOverlap;
+              if (dx < width) {
+                var canvas0 = buffer.getContext("2d");
+                canvas0.clearRect(0, 0, width, height);
+                canvas0.drawImage(canvas.canvas, dx, 0, width - dx, height, 0, 0, width - dx, height);
+                canvas.clearRect(0, 0, width, height);
+                canvas.drawImage(canvas0.canvas, 0, 0);
+              }
             }
+          } else {
+            canvas.clearRect(0,0,width,height);
           }
           start = start1;
         }
@@ -827,7 +894,7 @@ cubism_contextPrototype.horizon = function() {
         scale.domain([0, max_ = max]);
 
         // clear for the new data
-        canvas.clearRect(i0, 0, width - i0, height);
+        canvas.clearRect(i0, 0, iEnd, height);
 
         // record whether there are negative values to display
         var negative;
@@ -841,7 +908,7 @@ cubism_contextPrototype.horizon = function() {
           scale.range([m * height + y0, y0]);
           y0 = scale(0);
 
-          for (var i = i0, n = width, y1; i < n; ++i) {
+          for (var i = i0, n = iEnd, y1; i < n; ++i) {
             y1 = metric_.valueAt(i);
             if (y1 <= 0) { negative = true; continue; }
             if (y1 === undefined) continue;
@@ -865,7 +932,7 @@ cubism_contextPrototype.horizon = function() {
             scale.range([m * height + y0, y0]);
             y0 = scale(0);
 
-            for (var i = i0, n = width, y1; i < n; ++i) {
+            for (var i = i0, n = iEnd, y1; i < n; ++i) {
               y1 = metric_.valueAt(i);
               if (y1 >= 0) continue;
               canvas.fillRect(i, scale(-y1), 1, y0 - scale(-y1));
diff --git a/cubism.v1.min.js b/cubism.v1.min.js
index d8c13b1..56bab6d 100644
--- a/cubism.v1.min.js
+++ b/cubism.v1.min.js
@@ -1 +1 @@
-(function(a){function d(a){return a}function e(){}function j(a){return Math.floor(a/1e3)}function k(a){var b=a.indexOf("|"),c=a.substring(0,b),d=c.lastIndexOf(","),e=c.lastIndexOf(",",d-1),f=c.lastIndexOf(",",e-1),g=c.substring(f+1,e)*1e3,h=c.substring(d+1)*1e3;return a.substring(b+1).split(",").slice(1).map(function(a){return+a})}function l(a){if(!(a instanceof e))throw new Error("invalid context");this.context=a}function o(a,b){return function(c,d,e,f){a(new Date(+c+b),new Date(+d+b),e,f)}}function p(a,b){l.call(this,a),b=+b;var c=b+"";this.valueOf=function(){return b},this.toString=function(){return c}}function r(a,b){function c(b,c){if(c instanceof l){if(b.context!==c.context)throw new Error("mismatch context")}else c=new p(b.context,c);l.call(this,b.context),this.left=b,this.right=c,this.toString=function(){return b+" "+a+" "+c}}var d=c.prototype=Object.create(l.prototype);return d.valueAt=function(a){return b(this.left.valueAt(a),this.right.valueAt(a))},d.shift=function(a){return new c(this.left.shift(a),this.right.shift(a))},d.on=function(a,b){return arguments.length<2?this.left.on(a):(this.left.on(a,b),this.right.on(a,b),this)},function(a){return new c(this,a)}}function u(a){return a&16777214}function v(a){return(a+1&16777214)-1}function z(a){a.style("position","absolute").style("top",0).style("bottom",0).style("width","1px").style("pointer-events","none")}function A(a){return a+"px"}var b=a.cubism={version:"1.4.0"},c=0;b.option=function(a,c){var d=b.options(a);return d.length?d[0]:c},b.options=function(a,b){var c=location.search.substring(1).split("&"),d=[],e=-1,f=c.length,g;while(++e<f)(g=c[e].split("="))[0]==a&&d.push(decodeURIComponent(g[1]));return d.length||arguments.length<2?d:b},b.context=function(){function p(){var c=Date.now();return g=new Date(Math.floor((c-j-k)/b)*b),f=new Date(g-d*b),i=new Date(Math.floor((c-j)/b)*b),h=new Date(i-d*b),m.domain([f,g]),a}var a=new 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arguments.length<2?null:this};cubism_contextPrototype.metric=function(request,name){var context=this,metric=new cubism_metric(context),id=".metric-"+ ++cubism_id,start=-Infinity,stop,step=context.step(),size=context.size(),values=[],event=d3.dispatch("change"),listening=0,fetching;function prepare(start1,stop,callback){if(start1>start){var steps=Math.min(size,Math.round((start1-start)/step));if(!steps||fetching)return;fetching=true;steps=Math.min(size,steps+cubism_metricOverlap);var start0=new Date(stop-steps*step);request(start0,stop,step,function(error,data){fetching=false;if(error)return console.warn(error);var i=isFinite(start)?Math.round((start0-start)/step):0;for(var j=0,m=data.length;j<m;++j)values[j+i]=data[j];event.change.call(metric,start,stop);if(callback!=null)callback()})}else{var steps=Math.min(size,Math.round((start-start1)/step));if(!steps||fetching)return;fetching=true;var stop0=new Date(+start1+steps*step);request(start1,stop0,step,function(error,data){fetching=false;if(error)return console.warn(error);prevalues=[];for(var j=0,m=data.length;j<m;++j)prevalues[j]=data[j];values=prevalues.concat(values);event.change.call(metric,start,stop);if(callback!=null)callback()})}}function beforechange(start1,stop1){if(!isFinite(start))start=start1;if(start1>start)values.splice(0,Math.max(0,Math.min(size,Math.round((start1-start)/step))));else values.splice(stop1,Math.max(0,Math.min(size,Math.round((start-start1)/step))));start=start1;stop=stop1}metric.valueAt=function(i){return values[i]};metric.shift=function(offset){return context.metric(cubism_metricShift(request,+offset))};metric.on=function(type,listener){if(!arguments.length)return event.on(type);if(listener==null){if(event.on(type)!=null&&--listening==0){context.on("prepare"+id,null).on("beforechange"+id,null)}}else{if(event.on(type)==null&&++listening==1){context.on("prepare"+id,prepare).on("beforechange"+id,beforechange)}}event.on(type,listener);if(listener!=null){if(/^change(\.|$)/.test(type))listener.call(context,start,stop)}return metric};if(arguments.length>1)metric.toString=function(){return name};return metric};var cubism_metricOverlap=6;function cubism_metricShift(request,offset){return function(start,stop,step,callback){request(new Date(+start+offset),new Date(+stop+offset),step,callback)}}function cubism_metricConstant(context,value){cubism_metric.call(this,context);value=+value;var name=value+"";this.valueOf=function(){return value};this.toString=function(){return name}}var cubism_metricConstantPrototype=cubism_metricConstant.prototype=Object.create(cubism_metric.prototype);cubism_metricConstantPrototype.valueAt=function(){return+this};cubism_metricConstantPrototype.extent=function(){return[+this,+this]};function cubism_metricOperator(name,operate){function cubism_metricOperator(left,right){if(!(right instanceof cubism_metric))right=new cubism_metricConstant(left.context,right);else if(left.context!==right.context)throw new Error("mismatch context");cubism_metric.call(this,left.context);this.left=left;this.right=right;this.toString=function(){return left+" "+name+" "+right}}var cubism_metricOperatorPrototype=cubism_metricOperator.prototype=Object.create(cubism_metric.prototype);cubism_metricOperatorPrototype.valueAt=function(i){return operate(this.left.valueAt(i),this.right.valueAt(i))};cubism_metricOperatorPrototype.shift=function(offset){return new cubism_metricOperator(this.left.shift(offset),this.right.shift(offset))};cubism_metricOperatorPrototype.on=function(type,listener){if(arguments.length<2)return this.left.on(type);this.left.on(type,listener);this.right.on(type,listener);return this};return function(right){return new cubism_metricOperator(this,right)}}cubism_metricPrototype.add=cubism_metricOperator("+",function(left,right){return left+right});cubism_metricPrototype.subtract=cubism_metricOperator("-",function(left,right){return left-right});cubism_metricPrototype.multiply=cubism_metricOperator("*",function(left,right){return left*right});cubism_metricPrototype.divide=cubism_metricOperator("/",function(left,right){return left/right});cubism_contextPrototype.horizon=function(){var context=this,mode="offset",buffer=document.createElement("canvas"),width=buffer.width=context.size(),height=buffer.height=30,scale=d3.scale.linear().interpolate(d3.interpolateRound),metric=cubism_identity,extent=null,title=cubism_identity,format=d3.format(".2s"),colors=["#08519c","#3182bd","#6baed6","#bdd7e7","#bae4b3","#74c476","#31a354","#006d2c"];function horizon(selection){selection.on("mousemove.horizon",function(){context.focus(Math.round(d3.mouse(this)[0]))}).on("mouseout.horizon",function(){context.focus(null)});selection.append("canvas").attr("width",width).attr("height",height);selection.append("span").attr("class","title").text(title);selection.append("span").attr("class","value");selection.each(function(d,i){var that=this,id=++cubism_id,metric_=typeof metric==="function"?metric.call(that,d,i):metric,colors_=typeof colors==="function"?colors.call(that,d,i):colors,extent_=typeof extent==="function"?extent.call(that,d,i):extent,start=-Infinity,step=context.step(),canvas=d3.select(that).select("canvas"),span=d3.select(that).select(".value"),max_,m=colors_.length>>1,ready;canvas.datum({id:id,metric:metric_});canvas=canvas.node().getContext("2d");function change(start1,stop){canvas.save();var extent=metric_.extent();ready=extent.every(isFinite);if(extent_!=null)extent=extent_;var i0=0,max=Math.max(-extent[0],extent[1]);var iEnd=width;if(this===context){if(max==max_){if(start1<start){var dx=(start-start1)/step;iEnd=dx;if(dx<width){var canvas0=buffer.getContext("2d");canvas0.clearRect(0,0,width,height);canvas0.drawImage(canvas.canvas,0,0,width-dx,height,dx,0,width-dx,height);canvas.clearRect(0,0,width,height);canvas.drawImage(canvas0.canvas,0,0)}}else{var dx=(start1-start)/step;i0=width-dx-cubism_metricOverlap;if(dx<width){var canvas0=buffer.getContext("2d");canvas0.clearRect(0,0,width,height);canvas0.drawImage(canvas.canvas,dx,0,width-dx,height,0,0,width-dx,height);canvas.clearRect(0,0,width,height);canvas.drawImage(canvas0.canvas,0,0)}}}else{canvas.clearRect(0,0,width,height)}start=start1}scale.domain([0,max_=max]);canvas.clearRect(i0,0,iEnd,height);var negative;for(var j=0;j<m;++j){canvas.fillStyle=colors_[m+j];var y0=(j-m+1)*height;scale.range([m*height+y0,y0]);y0=scale(0);for(var i=i0,n=iEnd,y1;i<n;++i){y1=metric_.valueAt(i);if(y1<=0){negative=true;continue}if(y1===undefined)continue;canvas.fillRect(i,y1=scale(y1),1,y0-y1)}}if(negative){if(mode==="offset"){canvas.translate(0,height);canvas.scale(1,-1)}for(var j=0;j<m;++j){canvas.fillStyle=colors_[m-1-j];var y0=(j-m+1)*height;scale.range([m*height+y0,y0]);y0=scale(0);for(var i=i0,n=iEnd,y1;i<n;++i){y1=metric_.valueAt(i);if(y1>=0)continue;canvas.fillRect(i,scale(-y1),1,y0-scale(-y1))}}}canvas.restore()}function focus(i){if(i==null)i=width-1;var value=metric_.valueAt(i);span.datum(value).text(isNaN(value)?null:format)}context.on("change.horizon-"+id,change);context.on("focus.horizon-"+id,focus);metric_.on("change.horizon-"+id,function(start,stop){change(start,stop),focus();if(ready)metric_.on("change.horizon-"+id,cubism_identity)})})}horizon.remove=function(selection){selection.on("mousemove.horizon",null).on("mouseout.horizon",null);selection.selectAll("canvas").each(remove).remove();selection.selectAll(".title,.value").remove();function remove(d){d.metric.on("change.horizon-"+d.id,null);context.on("change.horizon-"+d.id,null);context.on("focus.horizon-"+d.id,null)}};horizon.mode=function(_){if(!arguments.length)return mode;mode=_+"";return horizon};horizon.height=function(_){if(!arguments.length)return height;buffer.height=height=+_;return horizon};horizon.metric=function(_){if(!arguments.length)return metric;metric=_;return horizon};horizon.scale=function(_){if(!arguments.length)return scale;scale=_;return horizon};horizon.extent=function(_){if(!arguments.length)return extent;extent=_;return horizon};horizon.title=function(_){if(!arguments.length)return title;title=_;return horizon};horizon.format=function(_){if(!arguments.length)return format;format=_;return horizon};horizon.colors=function(_){if(!arguments.length)return colors;colors=_;return horizon};return horizon};cubism_contextPrototype.comparison=function(){var context=this,width=context.size(),height=120,scale=d3.scale.linear().interpolate(d3.interpolateRound),primary=function(d){return d[0]},secondary=function(d){return d[1]},extent=null,title=cubism_identity,formatPrimary=cubism_comparisonPrimaryFormat,formatChange=cubism_comparisonChangeFormat,colors=["#9ecae1","#225b84","#a1d99b","#22723a"],strokeWidth=1.5;function comparison(selection){selection.on("mousemove.comparison",function(){context.focus(Math.round(d3.mouse(this)[0]))}).on("mouseout.comparison",function(){context.focus(null)});selection.append("canvas").attr("width",width).attr("height",height);selection.append("span").attr("class","title").text(title);selection.append("span").attr("class","value primary");selection.append("span").attr("class","value change");selection.each(function(d,i){var that=this,id=++cubism_id,primary_=typeof primary==="function"?primary.call(that,d,i):primary,secondary_=typeof secondary==="function"?secondary.call(that,d,i):secondary,extent_=typeof extent==="function"?extent.call(that,d,i):extent,div=d3.select(that),canvas=div.select("canvas"),spanPrimary=div.select(".value.primary"),spanChange=div.select(".value.change"),ready;canvas.datum({id:id,primary:primary_,secondary:secondary_});canvas=canvas.node().getContext("2d");function change(start,stop){canvas.save();canvas.clearRect(0,0,width,height);var primaryExtent=primary_.extent(),secondaryExtent=secondary_.extent(),extent=extent_==null?primaryExtent:extent_;scale.domain(extent).range([height,0]);ready=primaryExtent.concat(secondaryExtent).every(isFinite);var round=start/context.step()&1?cubism_comparisonRoundOdd:cubism_comparisonRoundEven;canvas.fillStyle=colors[2];for(var i=0,n=width;i<n;++i){var y0=scale(primary_.valueAt(i)),y1=scale(secondary_.valueAt(i));if(y0<y1)canvas.fillRect(round(i),y0,1,y1-y0)}canvas.fillStyle=colors[0];for(i=0;i<n;++i){var y0=scale(primary_.valueAt(i)),y1=scale(secondary_.valueAt(i));if(y0>y1)canvas.fillRect(round(i),y1,1,y0-y1)}canvas.fillStyle=colors[3];for(i=0;i<n;++i){var y0=scale(primary_.valueAt(i)),y1=scale(secondary_.valueAt(i));if(y0<=y1)canvas.fillRect(round(i),y0,1,strokeWidth)}canvas.fillStyle=colors[1];for(i=0;i<n;++i){var y0=scale(primary_.valueAt(i)),y1=scale(secondary_.valueAt(i));if(y0>y1)canvas.fillRect(round(i),y0-strokeWidth,1,strokeWidth)}canvas.restore()}function focus(i){if(i==null)i=width-1;var valuePrimary=primary_.valueAt(i),valueSecondary=secondary_.valueAt(i),valueChange=(valuePrimary-valueSecondary)/valueSecondary;spanPrimary.datum(valuePrimary).text(isNaN(valuePrimary)?null:formatPrimary);spanChange.datum(valueChange).text(isNaN(valueChange)?null:formatChange).attr("class","value change "+(valueChange>0?"positive":valueChange<0?"negative":""))}primary_.on("change.comparison-"+id,firstChange);secondary_.on("change.comparison-"+id,firstChange);function firstChange(start,stop){change(start,stop),focus();if(ready){primary_.on("change.comparison-"+id,cubism_identity);secondary_.on("change.comparison-"+id,cubism_identity)}}context.on("change.comparison-"+id,change);context.on("focus.comparison-"+id,focus)})}comparison.remove=function(selection){selection.on("mousemove.comparison",null).on("mouseout.comparison",null);selection.selectAll("canvas").each(remove).remove();selection.selectAll(".title,.value").remove();function remove(d){d.primary.on("change.comparison-"+d.id,null);d.secondary.on("change.comparison-"+d.id,null);context.on("change.comparison-"+d.id,null);context.on("focus.comparison-"+d.id,null)}};comparison.height=function(_){if(!arguments.length)return height;height=+_;return comparison};comparison.primary=function(_){if(!arguments.length)return primary;primary=_;return comparison};comparison.secondary=function(_){if(!arguments.length)return secondary;secondary=_;return comparison};comparison.scale=function(_){if(!arguments.length)return scale;scale=_;return comparison};comparison.extent=function(_){if(!arguments.length)return extent;extent=_;return comparison};comparison.title=function(_){if(!arguments.length)return title;title=_;return comparison};comparison.formatPrimary=function(_){if(!arguments.length)return formatPrimary;formatPrimary=_;return comparison};comparison.formatChange=function(_){if(!arguments.length)return formatChange;formatChange=_;return comparison};comparison.colors=function(_){if(!arguments.length)return colors;colors=_;return comparison};comparison.strokeWidth=function(_){if(!arguments.length)return strokeWidth;strokeWidth=_;return comparison};return comparison};var cubism_comparisonPrimaryFormat=d3.format(".2s"),cubism_comparisonChangeFormat=d3.format("+.0%");function cubism_comparisonRoundEven(i){return i&16777214}function cubism_comparisonRoundOdd(i){return(i+1&16777214)-1}cubism_contextPrototype.axis=function(){var context=this,scale=context.scale,axis_=d3.svg.axis().scale(scale);var format=context.step()<6e4?cubism_axisFormatSeconds:context.step()<864e5?cubism_axisFormatMinutes:cubism_axisFormatDays;function axis(selection){var id=++cubism_id,tick;var g=selection.append("svg").datum({id:id}).attr("width",context.size()).attr("height",Math.max(28,-axis.tickSize())).append("g").attr("transform","translate(0,"+(axis_.orient()==="top"?27:4)+")").call(axis_);context.on("change.axis-"+id,function(){g.call(axis_);if(!tick)tick=d3.select(g.node().appendChild(g.selectAll("text").node().cloneNode(true))).style("display","none").text(null)});context.on("focus.axis-"+id,function(i){if(tick){if(i==null){tick.style("display","none");g.selectAll("text").style("fill-opacity",null)}else{tick.style("display",null).attr("x",i).text(format(scale.invert(i)));var dx=tick.node().getComputedTextLength()+6;g.selectAll("text").style("fill-opacity",function(d){return Math.abs(scale(d)-i)<dx?0:1})}}})}axis.remove=function(selection){selection.selectAll("svg").each(remove).remove();function remove(d){context.on("change.axis-"+d.id,null);context.on("focus.axis-"+d.id,null)}};return d3.rebind(axis,axis_,"orient","ticks","tickSubdivide","tickSize","tickPadding","tickFormat")};var cubism_axisFormatSeconds=d3.time.format("%I:%M:%S %p"),cubism_axisFormatMinutes=d3.time.format("%I:%M %p"),cubism_axisFormatDays=d3.time.format("%B %d");cubism_contextPrototype.rule=function(){var context=this,metric=cubism_identity;function rule(selection){var id=++cubism_id;var line=selection.append("div").datum({id:id}).attr("class","line").call(cubism_ruleStyle);selection.each(function(d,i){var that=this,id=++cubism_id,metric_=typeof metric==="function"?metric.call(that,d,i):metric;if(!metric_)return;function change(start,stop){var values=[];for(var i=0,n=context.size();i<n;++i){if(metric_.valueAt(i)){values.push(i)}}var lines=selection.selectAll(".metric").data(values);lines.exit().remove();lines.enter().append("div").attr("class","metric line").call(cubism_ruleStyle);lines.style("left",cubism_ruleLeft)}context.on("change.rule-"+id,change);metric_.on("change.rule-"+id,change)});context.on("focus.rule-"+id,function(i){line.datum(i).style("display",i==null?"none":null).style("left",i==null?null:cubism_ruleLeft)})}rule.remove=function(selection){selection.selectAll(".line").each(remove).remove();function remove(d){context.on("focus.rule-"+d.id,null)}};rule.metric=function(_){if(!arguments.length)return metric;metric=_;return rule};return rule};function cubism_ruleStyle(line){line.style("position","absolute").style("top",0).style("bottom",0).style("width","1px").style("pointer-events","none")}function cubism_ruleLeft(i){return i+"px"}}(this);
\ No newline at end of file
diff --git a/src/context.js b/src/context.js
index 1dd29ef..444f927 100644
--- a/src/context.js
+++ b/src/context.js
@@ -6,42 +6,60 @@ cubism.context = function() {
       start1, stop1, // the start and stop for the next prepare event
       serverDelay = 5e3,
       clientDelay = 5e3,
+      seek = 0,
       event = d3.dispatch("prepare", "beforechange", "change", "focus"),
       scale = context.scale = d3.time.scale().range([0, size]),
       timeout,
       focus;
 
   function update() {
-    var now = Date.now();
-    stop0 = new Date(Math.floor((now - serverDelay - clientDelay) / step) * step);
-    start0 = new Date(stop0 - size * step);
-    stop1 = new Date(Math.floor((now - serverDelay) / step) * step);
-    start1 = new Date(stop1 - size * step);
-    scale.domain([start0, stop0]);
+    if(seek != 0){
+      stop0 = new Date(Math.floor(seek / step) * step);
+      start0 = new Date(stop0 - size * step);
+      stop1 = stop0;
+      start1 = start0;
+      scale.domain([start0, stop0]);
+    } else {
+      var now = Date.now();
+      stop0 = new Date(Math.floor((now - serverDelay - clientDelay) / step) * step);
+      start0 = new Date(stop0 - size * step);
+      stop1 = new Date(Math.floor((now - serverDelay) / step) * step);
+      start1 = new Date(stop1 - size * step);
+      scale.domain([start0, stop0]);
+    }
     return context;
   }
 
   context.start = function() {
-    if (timeout) clearTimeout(timeout);
-    var delay = +stop1 + serverDelay - Date.now();
-
-    // If we're too late for the first prepare event, skip it.
-    if (delay < clientDelay) delay += step;
-
-    timeout = setTimeout(function prepare() {
-      stop1 = new Date(Math.floor((Date.now() - serverDelay) / step) * step);
-      start1 = new Date(stop1 - size * step);
-      event.prepare.call(context, start1, stop1);
-
-      setTimeout(function() {
-        scale.domain([start0 = start1, stop0 = stop1]);
+    if(seek != 0) {
+      event.prepare.call(context, start1, stop1, function(){
         event.beforechange.call(context, start1, stop1);
         event.change.call(context, start1, stop1);
-        event.focus.call(context, focus);
-      }, clientDelay);
-
-      timeout = setTimeout(prepare, step);
-    }, delay);
+        event.focus.call(context, focus);  
+      });
+    } else {
+      // Realtime
+      if (timeout) clearTimeout(timeout);
+      var delay = +stop1 + serverDelay - Date.now();
+
+      // If we're too late for the first prepare event, skip it.
+      if (delay < clientDelay) delay += step;
+
+      timeout = setTimeout(function prepare() {
+        stop1 = new Date(Math.floor((Date.now() - serverDelay) / step) * step);
+        start1 = new Date(stop1 - size * step);
+        event.prepare.call(context, start1, stop1);
+
+        setTimeout(function() {
+          scale.domain([start0 = start1, stop0 = stop1]);
+          event.beforechange.call(context, start1, stop1);
+          event.change.call(context, start1, stop1);
+          event.focus.call(context, focus);
+        }, clientDelay);
+
+        timeout = setTimeout(prepare, step);
+      }, delay);
+    }
     return context;
   };
 
@@ -52,6 +70,14 @@ cubism.context = function() {
 
   timeout = setTimeout(context.start, 10);
 
+  // seek = fixed end time
+  // if seek = 0 moves back to real time
+  context.seek = function(_) {
+    if(!arguments.length) return seek;
+    seek = +_;
+    return update().stop().start();
+  };
+
   // Set or get the step interval in milliseconds.
   // Defaults to ten seconds.
   context.step = function(_) {
diff --git a/src/horizon.js b/src/horizon.js
index 3c779c0..200949a 100644
--- a/src/horizon.js
+++ b/src/horizon.js
@@ -55,17 +55,34 @@ cubism_contextPrototype.horizon = function() {
 
         // if this is an update (with no extent change), copy old values!
         var i0 = 0, max = Math.max(-extent[0], extent[1]);
+        var iEnd = width;
+
         if (this === context) {
           if (max == max_) {
-            i0 = width - cubism_metricOverlap;
-            var dx = (start1 - start) / step;
-            if (dx < width) {
-              var canvas0 = buffer.getContext("2d");
-              canvas0.clearRect(0, 0, width, height);
-              canvas0.drawImage(canvas.canvas, dx, 0, width - dx, height, 0, 0, width - dx, height);
-              canvas.clearRect(0, 0, width, height);
-              canvas.drawImage(canvas0.canvas, 0, 0);
+            if(start1 < start) {
+              // Need to repaint the left side (seeking, not realtime)
+              var dx = (start - start1) / step;
+              iEnd = dx;
+              if(dx < width) {
+                var canvas0 = buffer.getContext("2d");
+                canvas0.clearRect(0, 0, width, height);
+                canvas0.drawImage(canvas.canvas, 0, 0, width - dx, height, dx, 0, width - dx, height);
+                canvas.clearRect(0,0, width, height);
+                canvas.drawImage(canvas0.canvas, 0, 0);
+              }
+            } else {
+              var dx = (start1 - start) / step;
+              i0 = width - dx - cubism_metricOverlap;
+              if (dx < width) {
+                var canvas0 = buffer.getContext("2d");
+                canvas0.clearRect(0, 0, width, height);
+                canvas0.drawImage(canvas.canvas, dx, 0, width - dx, height, 0, 0, width - dx, height);
+                canvas.clearRect(0, 0, width, height);
+                canvas.drawImage(canvas0.canvas, 0, 0);
+              }
             }
+          } else {
+            canvas.clearRect(0,0,width,height);
           }
           start = start1;
         }
@@ -74,7 +91,7 @@ cubism_contextPrototype.horizon = function() {
         scale.domain([0, max_ = max]);
 
         // clear for the new data
-        canvas.clearRect(i0, 0, width - i0, height);
+        canvas.clearRect(i0, 0, iEnd, height);
 
         // record whether there are negative values to display
         var negative;
@@ -88,7 +105,7 @@ cubism_contextPrototype.horizon = function() {
           scale.range([m * height + y0, y0]);
           y0 = scale(0);
 
-          for (var i = i0, n = width, y1; i < n; ++i) {
+          for (var i = i0, n = iEnd, y1; i < n; ++i) {
             y1 = metric_.valueAt(i);
             if (y1 <= 0) { negative = true; continue; }
             if (y1 === undefined) continue;
@@ -112,7 +129,7 @@ cubism_contextPrototype.horizon = function() {
             scale.range([m * height + y0, y0]);
             y0 = scale(0);
 
-            for (var i = i0, n = width, y1; i < n; ++i) {
+            for (var i = i0, n = iEnd, y1; i < n; ++i) {
               y1 = metric_.valueAt(i);
               if (y1 >= 0) continue;
               canvas.fillRect(i, scale(-y1), 1, y0 - scale(-y1));
diff --git a/src/metric.js b/src/metric.js
index ff3e75f..4217136 100644
--- a/src/metric.js
+++ b/src/metric.js
@@ -56,25 +56,49 @@ cubism_contextPrototype.metric = function(request, name) {
       fetching;
 
   // Prefetch new data into a temporary array.
-  function prepare(start1, stop) {
-    var steps = Math.min(size, Math.round((start1 - start) / step));
-    if (!steps || fetching) return; // already fetched, or fetching!
-    fetching = true;
-    steps = Math.min(size, steps + cubism_metricOverlap);
-    var start0 = new Date(stop - steps * step);
-    request(start0, stop, step, function(error, data) {
-      fetching = false;
-      if (error) return console.warn(error);
-      var i = isFinite(start) ? Math.round((start0 - start) / step) : 0;
-      for (var j = 0, m = data.length; j < m; ++j) values[j + i] = data[j];
-      event.change.call(metric, start, stop);
-    });
+  function prepare(start1, stop, callback) {
+    if(start1 > start) {
+      var steps = Math.min(size, Math.round((start1 - start) / step));
+      if (!steps || fetching) return; // already fetched, or fetching!
+      fetching = true;
+      steps = Math.min(size, steps + cubism_metricOverlap);
+      var start0 = new Date(stop - steps * step);
+      request(start0, stop, step, function(error, data) {
+        fetching = false;
+        if (error) return console.warn(error);
+        var i = isFinite(start) ? Math.round((start0 - start) / step) : 0;
+        for (var j = 0, m = data.length; j < m; ++j) values[j + i] = data[j];
+        event.change.call(metric, start, stop);
+        if(callback != null) callback();
+      });
+    } else {
+      var steps = Math.min(size, Math.round((start - start1) / step));
+      if (!steps || fetching) return;
+      fetching = true;
+      // Must be seeking backward... don't need to overlap since we are 
+      // not in realtime
+      //steps = Math.min(size, steps + cubism_metricOverlap);
+      var stop0 = new Date(+start1 + steps * step);
+      request(start1, stop0, step, function(error, data) {
+        fetching = false;
+        if(error) return console.warn(error);
+        prevalues = []
+        for (var j = 0, m = data.length; j < m; ++j) prevalues[j] = data[j];
+        values = prevalues.concat(values);
+        event.change.call(metric, start, stop);
+        if(callback != null) callback();
+      });
+    }
   }
 
   // When the context changes, switch to the new data, ready-or-not!
   function beforechange(start1, stop1) {
     if (!isFinite(start)) start = start1;
-    values.splice(0, Math.max(0, Math.min(size, Math.round((start1 - start) / step))));
+
+    if(start1 > start)
+      values.splice(0, Math.max(0, Math.min(size, Math.round((start1 - start) / step))));
+    else
+      values.splice(stop1, Math.max(0, Math.min(size, Math.round((start - start1) / step))));
     start = start1;
     stop = stop1;
   }