"Part 1"

After the Tokyo Olympics, due to the economic crisis, Japan became full of criminals. The prison became privatized and the death penalty no longer exists but for vicious criminals they are sentenced to life imprisonment. Rio, a former detective, is sentenced to life imprisonment for a terrorist who exploded a nuclear plant. But one day she is transferred to a different prison. The prison is full of famous prisoners such as former idol, pro-wrestler, pleasure criminals, etc., and the prison is called “The Cougar’s Castle.” No one can leave the Cougar’s Castle alive. The fights of extreme girls is about to begin.

"Part 2"

Rio, a former detective, is imprisoned at “The Cougar’s Castle” as a terrorist for exploding a nuclear plant. A survival game is held to bet people’s lives. The murderous game does not end until the final survivor wins. Through the game, Rio finds out the secret of the Cougar’s Castle…