diff --git a/v6d2ctx/at_of.py b/v6d2ctx/at_of.py
index c39c244..e01ac74 100644
--- a/v6d2ctx/at_of.py
+++ b/v6d2ctx/at_of.py
@@ -22,7 +22,7 @@ class AtOf(Generic[K, V]):
         def of(key: K) -> V:
             try:
                 return bucket[key]
-            except IndexError:
+            except (IndexError, KeyError):
                 raise Implicit
 
         return at, of