diff --git a/knots/parallelism.scm b/knots/parallelism.scm
index 99f41b3..41ae676 100644
--- a/knots/parallelism.scm
+++ b/knots/parallelism.scm
@@ -118,8 +118,13 @@
                           (vector-ref result-vec index))
                          (lambda (result)
                            (match result
-                             (('exception . exn)
-                              (raise-exception exn))
+                             (('exception exn stack)
+                              (let ((knots-exn
+                                     (make-knots-exception stack)))
+                                (raise-exception
+                                 (make-exception
+                                  knots-exn
+                                  exn))))
                              (_
                               (vector-set! result-vec
                                            index