Juzo Ogami has never led a normal life. He was picked up by a criminal organization as a child and grew up to become a legendary hit man. But everything changes when he's bitten by a mysterious insect and becomes a teenager again! Can this battle-hardened assassin handle the rigors of middle school life?!

The entire home ec club has been abducted by assassins, and in the midst of this crisis, Ogami has no choice but to draw his gun in front of Shido. To rescue their classmates, Ogami and Shido team up to pursue the killers. Will they manage to recover their friends safely?