diff --git a/node_embed.module b/node_embed.module
index 1985f63..8c12a1b 100644
--- a/node_embed.module
+++ b/node_embed.module
@@ -70,7 +70,7 @@ function _node_embed_replacements($matches) {
 
   // Check if the node is a real node.
   if (!$node = node_load($matches[1])) {
-    return _node_embed_user_feedback(end($stack), $matches, 'invalid');
+    return $stack ? _node_embed_user_feedback(end($stack), $matches, 'invalid') : '';
   }
 
   // Add to stack.