This is an automatically translated description

Takemichi hasn't achieved anything since high school, and he has long since labelled himself a failure and resigned himself to his fate. But an accident that almost killed him can make him a hero. Now Takemichi is able to travel back in time 12 years to his school days. His actions can change the future. He is able to save the girl he has always loved from a tragic death at the hands of the Tokyo Manji gang.

Almost by accident, in the past, Takemichi catches the eye of Mikey, the leader of the To-Man, and becomes his friend. That gang of schoolchildren is nothing like the criminal gang that will drown the capital in blood in a few years. They are hooligans, but still good guys who never hurt girls.

The first journey into the past has already changed the future: Takemichi's best friend Akkun has become To-Man's manager. Perhaps he can tell us why Mikey, a guy you could trust, turned into a beast?