diff --git a/src/mudlib/zmachine/mud_ui.py b/src/mudlib/zmachine/mud_ui.py
index cfa4ae5..32e1e9d 100644
--- a/src/mudlib/zmachine/mud_ui.py
+++ b/src/mudlib/zmachine/mud_ui.py
@@ -107,7 +107,9 @@ class MudInputStream(zstream.ZInputStream):
         text = self._input_queue.get()
         if text:
             return ord(text[0])
-        return 0
+        # Player hit Enter with no text — return 13 (ZSCII Enter/Return)
+        # so "press any key" prompts work in a line-oriented MUD client.
+        return 13
 
     def feed(self, text: str):
         self._input_queue.put(text)