One late night, Greydon Cross comes home to find his family slaughtered and Satan himself standing before him. Fueled with rage, he rushes towards Satan but is struck down before he could have his revenge. Upon his death, God appears before Greydon and gives him a choice. He could choose to go to heaven and enjoy eternity in Gods kingdom, or he could choose to go to Hell, where God would grant him powers to seek out Satan and destroy him. There was one catch however; once Satan was destroyed Greydon would have to become Satan himself.
His desire for revenge too strong to ignore, Greydon agrees to Gods terms and descends to hell on a mission to assassinate the devil and avenge his family. Upon finding himself in hell, Greydon must battle his way through an army of demons, all the while discovering the limitations of his new powers.