From the back of the book:
Mighty Theseus is dead!
Felled by a treacherous blow in the labyrinth of King Minos, your brother Theseus lies dead and unavenged. The spirits of your ancestors cry out from Hades in anger, and Hermes, the messenger of the gods, appears to speed you on your way. For YOU are Altheus, the brother on whom this heroic task falls. YOU thirst for action. YOU must travel across the wild seas and lands of Ancient Greece, battling with demons, mythical creatures and powerful leaders. Brave Altheus - will the gods be on your side?