Greg Heffley stared at the sign on his bedroom door. It read, "Rodrick's Room. No Wimps Allowed." He sighed. Another day, another battle with his rule-breaking older brother, Rodrick.

Rodrick was at it again, turning their house into a chaotic mess. This time, he'd set up his drum set in the living room, practicing for his band, Loded Diper.

Greg's parents, oblivious to Rodrick's rule-breaking, were at work. Greg felt like the only sane person in the house. If only he could prove Rodrick's misdeeds.

Greg decided to keep a record of Rodrick's rule-breaking. He started writing in his diary, meticulously noting every detail. The first entry: "Rodrick's Drum Disaster."

The days passed, and Greg's diary filled up with more entries. "Rodrick's Late Night TV Marathon." "Rodrick's Mysterious Bathroom Lock-In." "Rodrick's Homework Hijinks."

One day, Greg came home to find his diary missing. He turned the house upside down searching for it, but it was nowhere to be found. Panic set in.

Rodrick emerged from his room, diary in hand. He'd found it and read everything. Greg could tell by his smug grin that he was in trouble.

Rodrick used the diary against Greg, blackmailing him with the threat of showing their parents. Greg had no choice but to give in to Rodrick's demands.