Let's Go to School

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.