A Roman centurion who had died in battle is resurrected from the dead by Zeus, who ordered the warrior to save his daughter, Athena, from a Demon God called Neff in the Underworld. To become able to withstand the perils, the warrior gets the ability to absorb spirit balls who turn him into an Altered Beast, a part animal, part human creature of formidable force. Between each level are small animations giving the player glimpses of Athena’s peril.
After the centurion arrives in Dis, he faces Neff himself, who becomes a rhinoceros monster. After he is defeated, a blue bird comes out of the ground and transforms back to Athena. Afterwards she is shown holding arms with her lycanthropic hero, thanking him for rescuing her.