diff --git a/Mutant-year-zero/sheet.json b/Mutant-year-zero/sheet.json
index 99a5a485da..5894bad087 100644
--- a/Mutant-year-zero/sheet.json
+++ b/Mutant-year-zero/sheet.json
@@ -1,6 +1,7 @@
 {
-    "html": "html",
-    "css": "css",
+    "html": "mutant.html",
+    "css": "mutant.css",
+    "preview": "",
     "authors": "Daniel",
     "instructions": "enjoy"
 }