A frail high school student receives the heart of a "legendary mercenary"?! The ultimate guerrilla warrior vs. the most fearsome delinquent high school... A school revenge action story begins!

High school student Shirube Boshiran returns to Japan after three years following a heart transplant overseas. Shortly after transferring to his local school, Haze High, he becomes the target of bullying. One day, when Ran is cornered by delinquents, a change occurs in his body...!

"Get angry—atone with blood!"

Memories and combat skills engraved in the heart awake within Ran. The counterattack of a high school boy awakened to immense power begins!