diff --git a/src/mudlib/zmachine/zstackmanager.py b/src/mudlib/zmachine/zstackmanager.py
index 18ea0fb..d37e76d 100644
--- a/src/mudlib/zmachine/zstackmanager.py
+++ b/src/mudlib/zmachine/zstackmanager.py
@@ -104,6 +104,7 @@ class ZStackBottom:
 
     def __init__(self):
         self.program_counter = 0  # used as a cache only
+        self.return_addr = None
         self.stack = []
         self.local_vars = [0 for _ in range(15)]
 
@@ -201,15 +202,14 @@ class ZStackManager:
         current_routine = self._call_stack[-1]
 
         # Depending on many things, return stuff.
-        if exiting_routine.return_addr is not None:  # type: ignore[possibly-missing-attribute]
-            if exiting_routine.return_addr == 0:  # type: ignore[possibly-missing-attribute]
+        if exiting_routine.return_addr is not None:
+            if exiting_routine.return_addr == 0:
                 # Push to stack
                 self.push_stack(return_value)
-            elif 0 < exiting_routine.return_addr < 0x10:  # type: ignore[possibly-missing-attribute]
+            elif 0 < exiting_routine.return_addr < 0x10:
                 # Store in local var
-                self.set_local_variable(exiting_routine.return_addr - 1, return_value)  # type: ignore[possibly-missing-attribute]
+                self.set_local_variable(exiting_routine.return_addr - 1, return_value)
             else:
                 # Store in global var
-                self._memory.write_global(exiting_routine.return_addr, return_value)  # type: ignore[possibly-missing-attribute]
-
+                self._memory.write_global(exiting_routine.return_addr, return_value)
         return current_routine.program_counter