Task: Story Composition
Input (English): Premise: The rock rolled down the hill. 
 Initial Context: It hit another smaller rock on the way down. 
 Original Ending: That rock started rolling down the hill as well. The first rock stopped when it hit a tree. The smaller rock kept rolling down the hill to the river. 
 New ending: Two smaller rocks started rolling down the hill as well. The first smaller rock stopped when it hit a tree. The other smaller rock kept rolling down the hill to the bottom. 
Output (English): It stopped at the bottom.