diff --git a/aio/tools/plunker-builder/builder.js b/aio/tools/plunker-builder/builder.js
index 3c7856a1af..8876520066 100644
--- a/aio/tools/plunker-builder/builder.js
+++ b/aio/tools/plunker-builder/builder.js
@@ -152,6 +152,7 @@ class PlunkerBuilder {
       // Matches main.ts or main.1.ts
       if (/^main(?:[.-]\w+)?\.ts$/.test(relativeFileName)) {
         content = fileTranslator.translate(content, mainTsRules);
+        relativeFileName = 'main.ts';
       }
 
       if (relativeFileName == 'systemjs.config.extras.js') {