In 1896, in a small city in New Jersey, John Humperdink Stover, a precocious young boy with a penchant for causing trouble, is expelled from a public school and sent to Miss Wandell's Select Academy for Young Ladies and Gentlemen. John's father Samuel, an upstanding newspaper publisher and editor, hopes that the private school will reform his son, but his hopes are soon dashed when John causes an explosion in his chemistry class and is expelled from his new school. Samuel decides to give John one last chance to reform himself by enrolling him at Lawrenceville, a distinguished preparatory school near Princeton, where John's brother Sambo received his early education. En route to Lawrenceville, John shares a carriage with Mr. Hopkins, the school's headmaster, whose stodginess has earned him the title of "The Old Roman." Unaware that Mr. Hopkins is the school's headmaster, John spins wild tales about his family history, and then grabs the horse reigns and takes the carriage on a wild ride. When John arrives at the school, he is assigned to the Green House, a residence hall filled with an assortment of oddly nicknamed boys. After Tough McCarty, the intimidating elder classman leader of the house, changes John's name to "Dink," he introduces him to Coffee Colored Angel, White Mountain Canary, Cheyenne Baxter, Poler Beekstein, and his new roommate, Butsey White. Dink's initiation begins when White Mountain Canary chases him through the campus and engages him in a fistfight. Dink wins the fight, and later trounces another challenger, Coffee Colored Angel. Though he loses a fight with Tough McCarty, Dink refuses to make peace with the boys and is ostracized for his stubbornness. When summer arrives, Dink joins his family at a beach house and vows never to return to Lawrenceville. At the beach, Dink befriends a group of boys who join him in a number of pranks, including one designed to embarrass a young girl named Connie Brown. The boys, posing as sophisticated and cultured suitors, arrive at Connie's house one by one and pretend to vie for her attentions. The stunt drives Connie to tears, and the boys decide to play the same trick on other girls. At summer's end, Dink decides to return to Lawrenceville for another opportunity to fight Tough. When he arrives at the school, Dink is surprised to learn that he has been reassigned to a new residence hall, the Kennedy House, which is supervised by Mr. Hopkins. At the house, Dink becomes fast friends with the wiry, straight-laced Joshua Montgomery Smeed, known also as "The Big Man," who helps Dink with his studies. McCarty and Dink continue their feud on the football field, where they tackle each other mercilessly until Hopkins suspends Dink from the team. Dink and McCarty put aside their differences during an important football game and eventually forge a close friendship. Dink later gains the respect of Mr. Hopkins when Mr. Hopkins discovers that Dink decided not to cheat, as he had planned to, on an important examination. Dink later apologizes to Mr. Hopkins for misunderstanding him, and Mr. Hopkins realizes that Dink has matured. At the end of the school year, Dink returns to his parents' beach house, and they are pleased to see that their son has finally reformed.