The wizard Abosandrus has summoned you to recover four magical gems - an emerald, an amethyst, a ruby, and a sapphire - known as the Keys of Ac heron for their power to open great rifts between worlds - or close them. Only the Keys can negate the necromantic spells of the demon lord Kronus, whose will it is to invade the world of Earth with a legion of wraiths, fiends, and other monsters from another dimension. The Lords of Creation scattered the Keys through space and time so that only in the most dire circumstances would they be brought together. Despite his sorcerous knowledge, Abosandrus has not the youth and strength for the task, but his magic can transport you between worlds long enough to recover each key- if you are lucky. Unfortunately, the dimensional portals Abosandrus can open from his abode are limited, and you must make a further journey on foot - often at great peril - to recover each of the gems. Time is short. Kronus presses the attack and, knowing of the Keys, will use his magic to block your quest. If he follows and finds you, he will burn you with the touch of the black fire that chills the soul. Nor will your sword arm be of much good against him, for he is immortal and cannot be slain ... ever.