Greg Heffley finds himself thrust into a new year and a new school where undersize weaklings share the corridors with kids who are taller, meaner and already shaving. Desperate to prove his new found maturity, which only going up a grade can bring, Greg is happy to have his not-quite-so-cool sidekick, Rowley, along for the ride. But when Rowleys star starts to rise, Greg tries to use his best friends popularity to his own advantage. Recorded in his diary with comic pictures and his very own words, this test of Greg and Rowleys friendship unfolds with hilarious results.