diff --git a/packages/behavior/src/actions.js b/packages/behavior/src/actions.js
index a49a2a4..5596c3c 100644
--- a/packages/behavior/src/actions.js
+++ b/packages/behavior/src/actions.js
@@ -22,6 +22,8 @@ class Actions {
   }
 
   set index(index) {
+    // Clear out the action promise.
+    this.promise = null;
     this._index = index;
   }
 
@@ -78,8 +80,6 @@ class Actions {
   }
 
   prologue() {
-    // Clear out the action promise.
-    this.promise = null;
     // Increment and wrap the index.
     this.index = (this.index + 1) % this.expressions.length;
     // If rolled over, the actions are finished.