Zen, an autistic teenage girl with powerful martial skills, gets money to pay Zin’s treatment, her sick mother, seeking out all the people who owe Zin money.

Captured international assassins are locked up inside a high-tech bunker known as the Killing Chamber. To break out of this concrete hell they must duel each other, fight deadly ninjas and battle against gangs of masked maniacs. And… if they survive this, they will have to confront Snakehead: the lethal, deranged top dog who will stop at nothing to kill ’em all!