diff --git a/collects/help/search.ss b/collects/help/search.ss
index fb653bac..937ec5f9 100644
--- a/collects/help/search.ss
+++ b/collects/help/search.ss
@@ -8,7 +8,7 @@
 ;; Almost nothing to do here -- the real work is done in the browser,
 ;; using javascript.
 
-(define (send-main-page #:sub [sub #f]
+(define (send-main-page #:sub [sub "index.html"]
                         #:fragment [fragment #f] #:query [query #f])
   (let* ([path (build-path (find-user-doc-dir) sub)]
          [path (if (file-exists? path) path (build-path (find-doc-dir) sub))])