Task: Story Composition
Input (English): Premise: I was taking my dog for a walk. 
 Initial Context: He saw a cat. 
 Original Ending: He leaped forward and the leash snapped. He ran a few blocks away and I lost him. A couple of days later, he showed back up at my front door. 
 Counterfactual Context: He didn't need to be on a leash.
Output (English): He leaped forward when he saw a cat. He ran a few blocks away and I lost him. A couple of days later, he showed back up at my front door.