Task: Story Composition
Input (English): Premise: Brent went scuba diving one afternoon with his friend. 
 Initial Context: They jumped in the water and started to descend. 
 Original Ending: Half an hour later Brent noticed his oxygen was almost depleted. His friend handed him a can of spare air. Brent safely ascended back to the boat and got more oxygen. 
 Counterfactual Context: His friend strayed and couldn't be found.
Output (English): Half an hour later Brent noticed his oxygen was almost depleted. His friend handed him a can of spare air when he showed up out of nowhere. Brent safely ascended back to the boat and got more oxygen.