diff --git a/syndicate/async.rkt b/syndicate/async.rkt
index d8baba7..0ab64a5 100644
--- a/syndicate/async.rkt
+++ b/syndicate/async.rkt
@@ -17,7 +17,7 @@
   (async* (lambda () body ...)))
 
 (define (async* thunk)
-  (call-with-continuation-prompt thunk prompt-tag))
+  (call-with-continuation-prompt thunk prompt-tag (lambda (k) (k))))
 
 (define (async?)
   (continuation-prompt-available? prompt-tag))