Kei is a high-school student who is bullied on a daily basis…and his classmates, teachers and parents don't seem to care. Pushed to his limits by the endless pain and humiliation, he accepts a strange proposal put to him by his childhood friend Akira; committing suicide together in order to end this nightmare.
The attempt fails – Kei surviving and Akira disappearing without a trace.

Months later, Kei stumbles upon "Over Bleed" - a website on street fighting. Several videos on this site feature a barely recognizable Akira, now going by the nickname "Bunen", easily flooring scores of skilled opponents. Depressed and sickened by his own helplessness, Kei comes up with a reckless plan to discover the truth about his friend – making his way from fight to fight until Bunen grants him a one-on-one battle…

Kei – nieszczęśliwy i codziennie prześladowny w szkole chłopak – postanawia, wspólnie ze swoim przyjacielem, Akirą, popełnić samobójstwo. Z nieudanej próby odebrania sobie życia Kei wychodzi cało, a Akira znika w niewyjaśnionych okolicznościach. Kilka miesięcy później Kei trafia na stronę internetową, na której można oglądać walczących między sobą ludzi. Na jednym z filmów Kei poznaje swojego przyjaciela, który zniknął – postanawia go odnaleźć tym samym wchodząc na ścieżkę bijatyk i przemocy.