Greg Heffley finds himself in a new school year, where small, weak students share the hallways with bigger, meaner, and already shaving. Trying to prove his newfound maturity, something only a higher grade can bring, Greg is glad his not-so-cool friend Rowley is along for the ride. But when Rowley's star begins to rise, Greg tries to capitalize on his best friend's popularity. Chronicled in his diary, complete with humorous drawings and his own words, this test of Greg and Rowley's friendship unfolds with hilarious results.