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: Malcolm's Mayhem. Sentence 1: The school bell rang. Sentence 2: As Malcolm sat down at his desk, a sudden realization hit him. Sentence 3: He had forgotten his homework. Sentence 4: He gulped as the classroom door opened, Mrs Davids wouldn't be happy.
In walked a substitute teacher and Malcolm sighed a breath of relief.