One day, fourth graders George and Harold pull a series of practical jokes at the school's football game, from putting black pepper in the cheerleaders' pom-poms to filling the ball with helium, which causes the school to forfeit. The next day, their principal Mr. Krupp reveals that he now has a videotape of them preparing their pranks. Mr. Krupp blackmails George and Harold: unless they obey him, he will give copies of the tape to the football team. The boys wake up at 6 AM to wash his car and mow the grass for Mr. Krupp, not smile at all during school time and do extra homework. In order to escape this, George orders a "3-D Hypno-Ring" from the Li’l Wiseguy Novelty Company which they receive after 4–6 weeks of grueling labor. Purposefully arriving late the next day so they would be sent to the office, the boys hypnotize Mr. Krupp and Harold replaces the video with one of his little sister's "Boomer the Purple Dragon" sing-along videos.