Jolan has become a robust kid who is interested in everything. The strange signs he draws without knowing their meaning thoroughly intrigue his parents. During one escapade, he makes friends with a boy his age. The child seems to be lost. Along with being deaf and mute, he cannot answer questions raised by his mysterious presence.
Kriss de Valnor, the deadly warrior-woman and Thorgal's arch enemy, has Thorgal's and Aaricia's son abducted. She demands that Thorgal and Aaricia go on a quest to find the magical mask if they want to save their son.
Theseus, prince of Athens, awakens injured and bound inside an unknown hut. Facing him stands his captor - a mighty, bull-headed man! There, at the centre of the labyrinth built by engineer Dedalus for the king of Crete, Minos, Theseus is astonished to discover that the blood-thirsty monster that the legends describe is in fact a rational being named Asterios, who begins to recount the story of his life. Between the young Athenian sacrifice and the feared creature, grudging respect emerges...