This book describes Greg Heffley's worst summer ever. He wants to go to the beach for the family vacation, but is told by his parents that they don't have enough money. So they just go to the pool instead where Greg gets a crush on the lifeguard, Heather Hills. Greg had been begging for years for a dog and the family gets one. He wishes that he had never asked for one due to the new dog prefering to sleep in Greg's bed. Him and his friend Rowley have a fight and aren't friends for almost the whole summer.