diff --git a/knots.scm b/knots.scm
index 05b2a1a..01e3738 100644
--- a/knots.scm
+++ b/knots.scm
@@ -67,6 +67,58 @@
 (define* (print-backtrace-and-exception/knots
           exn
           #:key (port (current-error-port)))
+  (define (get-string port stack)
+    (define stack-len
+      (stack-length stack))
+
+    (let ((knots-stacks
+           (map knots-exception-stack
+                (filter knots-exception?
+                        (simple-exceptions exn)))))
+
+      (let* ((stack-vec
+              (stack->vector stack))
+             (stack-vec-length
+              (vector-length stack-vec)))
+        (print-frames (list->vector
+                       (drop
+                        (vector->list stack-vec)
+                        (if (< stack-vec-length 5)
+                            0
+                            4)))
+                      port
+                      #:count (stack-length stack)))
+      (for-each
+       (lambda (stack)
+         (let* ((stack-vec
+                 (stack->vector stack))
+                (stack-vec-length
+                 (vector-length stack-vec)))
+           (print-frames (list->vector
+                          (drop
+                           (vector->list stack-vec)
+                           (if (< stack-vec-length 4)
+                               0
+                               3)))
+                         port
+                         #:count (stack-length stack))))
+       knots-stacks)
+      (print-exception
+       port
+       (if (null? knots-stacks)
+           (stack-ref stack
+                      (if (< stack-len 4)
+                          stack-len
+                          4))
+           (let* ((stack (last knots-stacks))
+                  (stack-len (stack-length stack)))
+             (stack-ref stack
+                        (if (< stack-len 3)
+                            stack-len
+                            3))))
+       '%exception
+       (list exn))))
+
   (let* ((stack
           (match (fluid-ref %stacks)
             ((stack-tag . prompt-tag)
@@ -75,56 +127,25 @@
                          0 (and prompt-tag 1)))
             (_
              (make-stack #t))))
-         (stack-len
-          (stack-length stack))
+         (string-port
+          (open-output-string))
          (error-string
-          (call-with-output-string
-            (lambda (port)
-              (let ((knots-stacks
-                     (map knots-exception-stack
-                          (filter knots-exception?
-                                  (simple-exceptions exn)))))
+          (with-exception-handler
+              (lambda (exn)
+                (display (get-output-string string-port)
+                         port)
+                (close-output-port string-port)
+                (display "\n\n" port)
 
-                (let* ((stack-vec
-                        (stack->vector stack))
-                       (stack-vec-length
-                        (vector-length stack-vec)))
-                  (print-frames (list->vector
-                                 (drop
-                                  (vector->list stack-vec)
-                                  (if (< stack-vec-length 5)
-                                      0
-                                      4)))
-                                port
-                                #:count (stack-length stack)))
-                (for-each
-                 (lambda (stack)
-                   (let* ((stack-vec
-                           (stack->vector stack))
-                          (stack-vec-length
-                           (vector-length stack-vec)))
-                     (print-frames (list->vector
-                                    (drop
-                                     (vector->list stack-vec)
-                                     (if (< stack-vec-length 4)
-                                         0
-                                         3)))
-                                   port
-                                   #:count (stack-length stack))))
-                 knots-stacks)
-                (print-exception
+                (backtrace port)
+                (simple-format
                  port
-                 (if (null? knots-stacks)
-                     (stack-ref stack
-                                (if (< stack-len 4)
-                                    stack-len
-                                    4))
-                     (let* ((stack (last knots-stacks))
-                            (stack-len (stack-length stack)))
-                       (stack-ref stack
-                                  (if (< stack-len 3)
-                                      stack-len
-                                      3))))
-                 '%exception
-                 (list exn)))))))
+                 "\nexception in print-backtrace-and-exception/knots: ~A\n"
+                 exn)
+                (raise-exception exn))
+            (lambda ()
+              (get-string string-port stack)
+              (let ((str (get-output-string string-port)))
+                (close-output-port string-port)
+                str)))))
     (display error-string port)))