Legendary hitman Juzo Ogami has never failed an assignment. But after a mission, he's stung by a mysterious wasp and wakes up in the body of a 13-year-old boy! And to make things even weirder, he receives a bizarre new order: infiltrate a middle school. Now the once-feared assassin must balance the chaos of school life with his deadly work, all while searching for a way to regain his adult body!
E1
At 39, legendary hitman Juzo Ogami is stung by a mysterious wasp-like bioweapon and passes out. When he wakes up in Z.O.O.'s lab, he's shocked to find himself in the body of a middle schooler. His next mission: infiltrate a middle school. Though reluctant at first, Ogami unexpectedly discovers the joy of learning, until a suspicious intruder storms the school.
E2
The wasp that stung Juzo was created by Mitsuoka Pharmaceuticals, and it turns out that the daughter of the company's president, Noren Mitsuoka, is in Juzo's class. Beautiful, brilliant, and athletic, she's untouchable. Hoping she may hold a clue to restoring his original body, Juzo discovers that Noren works at a ramen shop and starts forming a connection with her. But then, Noren is abducted...
E3
When Juzo falls behind in school, his classmate Ryo Shiraishi starts tutoring him. He also joins the Home Ec Club run by Ryo's older sister, Chisato. Noren joins too, hoping it'll help with making ramen. Then, after Mitsuoka Pharma announces that whoever marries Noren will inherit the company, a cornered Noren blurts out something completely unexpected!
E4
Juzo is still uneasy about pretending to date Noren. But then Shin Kohazame, a middle-school assassin from the Chinese underworld group Yuigan, transfers into her school to become her fiancé and claim Mitsuoka Pharmaceutical's research and new drug. Shin challenges Noren's "boyfriend" Juzo to a duel, and their battle begins!
E5
Juzo and the Home Ec Club bring rice balls to the baseball team, where they meet elite ""Unicorn"" Tenma Tendo. An ace in baseball, soccer, and basketball, Tenma boasts that he'll become a "triple threat superhuman." When he challenges Juzo to futsal simply because he's "in the way" and mocks the Home Ec Club as a pointless play club, Juzo accepts.
E6
Juzo and Tenma's futsal showdown begins. With his astonishing physical ability, Tenma overwhelms the Home Ec Club team of Juzo, Shin, and Kito. Sensing that Juzo is no ordinary opponent, Tenma drops the handicap and starts playing for real. Juzo and the others fight desperately to keep up with Tenma's dominant performance, but how will the match end?
E7
Juzo and Noren end up on a double date with Chisato and Tenma. The four enjoy shopping and lunch, but the moment the movie starts, Juzo mysteriously reverts to his adult body! He rushes to the restroom, only for Noren to be kidnapped again. Chasing the culprit's car to a stadium, Juzo and Tenma face Kazuma and Eiji Rindou, assassin brothers from the industry's top organization, JARDIN.