Task: Story Composition
Input (English): Premise: I always get excited for costume parties. 
 Initial Context: I got invited to one this weekend. 
 Original Ending: I  could not find a good costume in time. I decided to design the perfect mask. I ended up having the best disguise at the party. 
 Counterfactual Context: No one was throwing any costume parties this weekend.
Output (English): I decided to throw my own, but could not find a good costume in time. I decided to design the perfect mask. I ended up having the best disguise at the party.