diff --git a/tools/make-books.sh b/tools/make-books.sh
index 79729df..2562bfb 100755
--- a/tools/make-books.sh
+++ b/tools/make-books.sh
@@ -37,7 +37,7 @@ pandoc -o $DIR_DOWNLOADS/$OUTPUT_CN.epub --metadata title="$TITLE_CN" --metadata
 epubcheck $DIR_DOWNLOADS/$OUTPUT_CN.epub
 epubcheck $DIR_DOWNLOADS/$OUTPUT_CN.epub
 
-cd ./tools
+cd ./tools || exit
 
 # Generate PDFs 
 npm run make-pdf --source=$INPUT_EN --destination=$OUTPUT_EN