When, in 1850, the brig Amaryllis was swallowed in a hurricane, the captain and all the crew were swallowed too. Thirty years later, Geneva Reade, the captain's ageing widow, was still waiting, certain that her husband would send her a message from the bottom of the sea. Someone else was waiting, too, a sad lost man she called by the single name Seward, though she had known him by another name in happier days, before the Amaryllis was lost. Into this haunted situation comes at last another Geneva, called Jenny, the widow's granddaughter, to stay with her in her house on the beach. The three of them, Gran, Jenny, and the man Seward, are drawn into a kind of deadly game with each other and with the sea, a game that only the sea knows how to win.