diff --git a/async.coffee b/async.coffee
index 06f5258..5af80fe 100644
--- a/async.coffee
+++ b/async.coffee
@@ -90,11 +90,11 @@ module.exports = async =
 
   detectSeries: Q.promised (arr, iterator, _notFound=undefined) ->
     return Q _notFound if arr.length is 0
-    iterator(arr[0]).then (ok) ->
+    Q(iterator(arr[0])).then (ok) ->
       if ok
         arr[0]
       else
-        async.detectSeries arr[1..], iterator
+        async.detectSeries arr[1..], iterator, _notFound
 
   # [a] -> (a -> P b) -> [a]
   # basically a swartzian transform