Argo, the ancient ship, has returned and hides beneath Urtha's fortress in Alba. Jason and the Argonauts are aboard her, enchanted into sleep. Niiv is still Merlin's lover, still seeking magic and mysteries, still a delight and torment to him.

Something is wrong in Alba. An unknown force is affecting the land. The omens are frightening. The feckless Sons of Llew arrive, having stolen their uncle's chariot and horses once again. They bring news of hostels, gateways between the worlds of the living and the dead. An enormous gathering of the Shades, of the dead and the unborn, are being drawn to them.

Meanwhile, Kymon and Munda, Urtha's son and daughter, are coming of age. Kymon is angry, boastful, ready to fight the Shades of Heroes, and violently annoyed by his father's diplomacy. Munda, on the other hand, is possessed of the Sight and welcomes the new, strange force in the land. She breaks taboo to visit one of the hostels. She comes back speaking of the Killer of Kings, the son of Jason.

And as Merlin walks in and out of time, clinging to his magic and the remains of his youth, the forces set in motion will determine the fate of kings and kingdoms alike.