At a sporting store, Hal wants to buy a speedo, but Lois stands strong in her refusal because she knows they're going to be in close quarters with the conservative Kenarbans and wants him to get swin trunks. He gets locked out of a dressing room at a department store wearing a skimpy bathing suit and when he calls to Malcolm for help. He pretends not to know him because he's trying to impress a girl. Soon Hal is arrested and almost becomes a registered sex offender. Meanwhile, Reese plays with a spear gun and Dewey knocks over a basketball hoop, much to Lois' dismay.
At Marlin Academy, Francis is horrified when his friend Eric turns eighteen and decides to leave school before graduation and go work on a fishing ship in Alaska making mad money. He gives him a tape of nude girls to remember him by.
At the Wilkerson house, Lois berates Malcolm for what happened and orders him to apologize for once. Hal seemingly refuses to talk to him and tells Reese to close the door in his face. Soon Lois is arguing with Francis on the phone. He implores his mother to let him do the same thing, but she refuses. Francis tells her it isn't worth the money and they know he's flunking anyway. Lois stays strong and orders him to stay in school until he graduates. Francis gets so upset that he slams the phone down and the phone falls on his foot. In pain, he stumbles against a trophy cabinet, breaking it and falling to the ground. Then, the trophy cabinet falls on him.
The Wilkerson family goes on vacation with the Kenarbans on a houseboat. Malcolm is psyched when his father seems to have forgiven him for the department store incident, and they plan to do a little father/son fishing on their vacation. Some cute cheerleaders come by in bikinis on a speedboat and invite Malcolm, Reese and Stevie to come play with them. While Malcolm and Hal are bored out of their minds fishing in the dingy (and not catching anything), Reese and Stevie fashion a raft of sorts and paddle their way to the girls' cheerleading camp. Meanwhile, Dewey decides to go on a rope swing over the water, but is too scared to let go of the rope and hangs there for hours getting sunburned. Finally, Lois has to throw rocks at Dewey to get him to let go of the rope.
That night on the houseboat, Dewey is bruised and sunburned, Malcolm is miserable, Reese and Stevie can't stop smiling, and Abe Kenarban is mopey. Abe and Kitty Kenarban end up arguing in their room, but the walls on the houseboat are thin, and the Wilkersons hear how Abe would rather be in a suite in Hawaii, but NOOO, Kitty had to have this awful houseboat vacation because the Wilkersons can't afford Hawaii.
Meanwhile at Marlin Academy, Commandant Spangler is unsympathic of the huge gash in Francis's leg and in fact gives the boy a hammer so that he can get started fixing the trophy case that he broke. He loses his patience and goes to a cheap lawyer, and by faking his parents' signatures he gets himself emancipated and leaves school for Alaska.
The next day, Lois saddles Reese with caring for his baby brother, so Reese and Stevie ditch Dewey on a buoy while they paddle back to the cheerleading camp. Malcolm spends another boring day sitting in a dingy with Hal not catching any fish. Finally, he catches a fish, and he and his father start the bonding process. At that moment the cutie girls speed by again, and Malcolm finds bikini tops and Reese's shirt floating in the water. He can't stand it anymore, pushes his father overboard and takes the dingy to go after the girls.
Lois, back on the houseboat, encourages Kitty to talk to her husband when he continues to pout. They start another fighting match behind thin walls, and when Lois hears things turn violent, she busts in... only to seriously regret walking in on the Kenarbans having sex.
Returning home, Lois punishes Malcolm and Reese for carelessly abandoning Hal and Dewey on the buoy, with three weeks of slave labor in the house. Knowing his relationship with his father will never be the same, Malcolm thinks it was worth it because he can't stop smiling. Meanwhile, Hal decides to reach out to Dewey and plans a little father/son ventriloquism, which both seem to enjoy. Soon Lois is furious when she learns that Francis quit school and has left for Alaska. Hal reminds her that he needs their permission to leave school. Lois tells him that Francis doesn't need to because he got legally emancipated.