In this task, you're given a four sentences of story written in natural language. Your job is to complete end part of the story by predicting appropriate last sentence which is coherent with the given sentences.

Sentence1: Roy walked on the beach and saw a sand castle near the surf. Sentence2: The water was approaching the castle more and more. Sentence3: Roy felt compelled to save the creation. Sentence4: He dug a trench around the castle and kept watch.
High tide came and went, but Roy managed to save the castle.