Plot
Visiting the local public pool with summer vacation starting, the Heffleys run into Lenwood Heath, a reformed delinquent friend of Rodrick's who works as a lifeguard there. He attends Spag Union, a strict disciplinarian military school that begins in the eighth grade. Frank notices that Greg is about to start that grade and considers signing him up. After learning that Greg spent his entire first day playing video games, Frank revokes this privilege, leading to Susan urging Frank to spend more time with him; he attempts to do so, but Greg's indifference annoys him.
Rowley invites Greg to the local country club. Initially reluctant, he joins Rowley and discovers that his crush, Holly Hills, teaches tennis there. After Rodrick learns that Holly's elder sister, Heather, whom he has a crush on, additionally works there, he asks Greg to help him sneak in. Frank surprises Greg with a non-paying summer internship at his job, hoping they can bond. Disliking the idea, Greg lies about having received a job at the club, to his parents' delight.
Rowley invites Greg on a family trip to a rented beach house near the boardwalk. Before they leave, Frank and Susan give Greg an impractical starter mobile phone that only allows him to call home or 911. Greg becomes increasingly creeped out by how close the Jeffersons are and secretly uses their laptop to email Susan into rescuing him. The family becomes suspicious after he inadvertently sends the email to everyone on the contact list; he desperately tries to call home using his new phone, but ends up accidentally calling 911 instead, leading to Rowley's father nearly being arrested when he absentmindedly answers the door with a knife in his hand. Greg is sent home early, and Frank starts to see Rowley as a bad influence.
A few days later, Rowley informs Greg that he is no longer allowed to invite him to the club, but he constantly sneaks in by impersonating members. They eventually reconcile as Greg gets Löded Diper a gig for Heather's upcoming sweet sixteen, to Rodrick's delight. During another visit, Rowley's father confronts Frank and Greg over the latter's reckless smoothie purchasing. Learning the truth about his son's deception, Frank expresses his disappointment with him. Shortly after, Rodrick reveals to him that a Spag Union disc has been mailed to them, to his horror.
Rodrick urges Greg to go on a camping trip for "Wilderness Explorers" with his classmates to impress Frank. During it, after overhearing Frank's superior, Stan Warren, insult him over his lack of camping skills, Greg sets a trap with his friends and sneaks into Stan's tent, where he discovers that their troop has been secretly using household appliances. Stan discovers Greg and insults him, but Frank soon chastises him for faking his camping skills before he runs into Greg's trap, humiliating himself. At a motel on the way home, Frank confesses he never liked camping and decides not to send Greg to Spag Union, to his surprise and delight. He also talks to him about learning from mistakes and taking responsibility, making them both realize they are more alike than they thought.
At Heather's sweet sixteen a few days later, Löded Diper performs with Rodrick on lead vocals to try and serenade her. The performance soon goes awry as a disgusted Heather attempts to assault him, ending the party in disaster even though Holly enjoyed it, and she and Greg become a couple and spend the rest of their summer together with Rowley and the rest of the Heffleys.
