Yoshioka (Tatsuya Nakazawa), imprisoned for killing a yakuza boss, and Kubota (Koki Tora), jailed for murdering his own father, are sent to a prison island where only death awaits. No sooner do they arrive than they are given a hellish “welcome” by the warden, Nakano (Yoshiyuki Yamaguchi), before being thrown into a communal block filled with dangerous inmates. There, they learn of a brutal underground fighting arena— groin strikes, eye gouging, biting… anything goes. Can the two survive long enough to escape the island alive? A high-octane, brutally real battle movie, where pride and fists collide, is born.