Task: Story Composition
Input (English): Premise: Every day at school, Billy ate tacos. 
 Initial Context: One day his friend gave him tuna fish. 
 Original Ending: He put the tuna in the taco. It tasted delicious! Billy ate tuna fish tacos from then on. 
 Counterfactual Context: His friend doesn't want to give him a tuna fish.
Output (English): He stole some tuna and put the tuna in the taco. It tasted delicious! Billy ate tuna fish tacos from then on.