In this task, you're given the title of a five-sentence story and the first four sentences. Your job is to write the last sentence of the story such that it seamlessly connects with the rest of the story.

Title: Apartment. Sentence 1: The new apartment smelled terrible. Sentence 2: They moved in only because they were desperate. Sentence 3: They couldn't find the source of the smell. Sentence 4: They even called in an exterminator.
They found a dead rat under the kitchen sink that was causing it.