Kairo is a man engulfed by his sin, distorted by violence and past tragedies. He faces a life-altering betrayal that thrusts his soul into the never-ending war between Heaven and Hell. Following this betrayal, Kairo's soul wanders to the gates of Hell, where his guardian angel puts him through one final test of morality. After passing the test, Kairo is offered a chance at redemption. He must fight as a warrior of God, against the greatest powers of evil Earth has ever known, the 7 Deadly Sins. Kairo begins his journey in the spirit realm of Limbo, the in-between of life and death. He ventures through Limbo in search of the 7 Deadly Sins, the rulers of darkness threatening God's throne.