On a cruise through the Greek islands, a man encounters a handsome father and his son. He is strangely drawn to his fellow travellers, and discovers with some elation that they will all share a cabin aboard ship.
Tricks of the light seem to join the pair into a single being when they walk ashore, and at times a third, much larger, being appears to join them.
Is the protagonist hallucinating, or is he experiencing repressed homosexual desires? Or is something darker and more ancient at work? Blackwood weaves a poetic, erotically charged tale against the exotic backdrop of the Greek islands.