Task: Story Composition
Input (English): Premise: Brad took a trip to Las Vegas in December. 
 Initial Context: He flew on a plane to get there. 
 Original Ending: He stayed in a hotel with an amusement park inside. He played the slots while he was there. He won five thousand dollars and came home the next day. 
 Counterfactual Context: He went for his 15th birthday.
Output (English): He stayed in a hotel with an amusement park inside. He played on the arcade games while he was there. He didn't win anything, but he came home the next day.