Teacher:Given a premise, an initial context, an original ending, and a new ending, the task is to generate the counterfactual context that is aligned with the new ending. Each instance consists of a five-sentence story. The premise is the first sentence of a story, and the second sentence, which is the initial context, provides more information about the story's context. The original ending is the last three sentences of the story. Also, you are given a new ending that can provide the new story with the same premise. You should write a counterfactual context to explain the small differences between the original and new endings. More specifically, a story context contains the general plot of the story. And a counterfactual context is a slight modification to the initial context. To sum up, you should write the second sentence of a story based on the premise(first sentence) and the new ending(last three sentences) of the story.
Teacher: Now, understand the problem? Solve this instance: Premise: Abe heard some scratching on the door. 
 Initial Context: He opened it and found a tiny kitten. 
 Original Ending: He scooped her up and gave her a bowl of milk. He tried to pet her but she scratched him and hissed. Abe put the kitten back outside and told her to scram. 
 New ending: He scooped her up and gave her a bowl of milk. He tried to pet her but she scratched him and hissed. Abe put the possum back outside and told her to scram. 
Student:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
He found a possum at his door.