Mysteriously transformed in a kid, legendary hitman Juzo poses as a student to investigate a middle school. Later, he encounters a suspicious intruder.

Juzo discovers Mitsuoka Pharmaceuticals created the wasp and befriends the president's aloof daughter Noren. As he slowly befriends her, she's kidnapped.

Juzo turns to a classmate to catch up on his studies and joins the home economics club with Noren. Mitsuoka Pharmaceuticals makes a big announcement.

Juzo's cover as Noren's boyfriend comes under fire when a young assassin transfers in and challenges Juzo to a duel in a bid to become Noren's fiancé.

While on an errand, the Home Economics Club runs into Tenma, a brash multi-sport ace who challenges Juzo to a futsal match. Will Juzo take him on?

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?

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.

Kazuma wields powerful hypnosis, while Eiji launches a brutal assault with explosive golf balls. They, too, are assassins chasing Mitsuoka Pharmaceutical’s secrets. Juzo struggles as Kazuma turns civilians against him. And Kazuma has already placed a certain hypnotic spell on Noren. To save her, Juzo races to her side...

Juzo races to Noren’s side. Meanwhile, Tenma and Eiji clash in an outrageous soccer-vs.-explosive-golf battle. Tenma prepares to end the fight with a move he developed in practice. But at the end of the life-or-death struggle against Kazuma and Eiji, the unconscious Noren awakens, and the first thing she sees is...

After Kazuma’s hypnosis makes Noren fall deeply for Juzo, she launches an all-out attack on his heart. But when Juzo gently turns her down, she tries to jump from the roof! Desperate to undo the spell, Juzo takes Noren to meet Kazuma at an amusement park, only to end up alone with her on a Ferris wheel, where things take a dangerously romantic turn?!

With more assassins gathering at school, Ogami organizes the first-ever Hitman Summit in hopes of keeping everyone under control. However, the meeting quickly descends into chaos as the eccentric personalities clash. Meanwhile, a heated ramen challenge draws unexpected attention, and a mysterious girl makes a surprising appearance that may change everything.