Task: Story Composition
Input (English): Premise: Carlos played the tuba in his local marching band. 
 Initial Context: Lately, his tuba was not pronouncing the notes as loudly. 
 Original Ending: Carlos plunged his hand into the tuba. He felt something move! A mouse had built a nest inside Carlos' tuba. 
 Counterfactual Context: Lately, his tuba was pronouncing the notes really well.
Output (English): Carlos was happy with his tuba. He could play it all day long. The Tuba was really clean on the inside and sounded great.