Task: Story Composition
Input (English): Premise: The Denver Broncos starting quarterback was injured. 
 Initial Context: Brock was their backup quarterback. 
 Original Ending: He took practice repetitions all week. Brock was ready to start their next game. He had a spectacular performance. 
 Counterfactual Context: Mick was their backup quarterback.
Output (English): Mick took practice repetitions all week. Mick was ready to start their next game. He had a spectacular performance.