When Elayan pirates attack Seahold (Sausalito), Rana and Frederic are taken prisoner and carried to the Far Alone Isles (the Farallon Islands). Led by an enigmatic young woman called Ardra who is the niece of Prince Palomon, the reivers have been devaastating the coastal holdings of Westria. The prisoners’ plans to escape are complicated when Ardra becomes attracted to Frederic, and he to her. Rana becomes a kitchen drudge and barely escapes rape by one of the pirates. Traumatized, she keeps to the wilder parts of the island, and in a tide-pool finds a jewel that can only be the Sea Star.
They must get the Jewel to Julian. Frederic is severely wounded covering Rana’s escape. In a small boat she escapes the pursuing pirates, but her craft sinks. She resigns herself to drowning, but the power of the Sea Star alerts Sea Mother, Guardian of the ocean’s creatures, who sends a whale to carry her to the Floating Island, where dolphins teach her their speech. Sea Mother instructs them to take her to Julian.
Meanwhile, Julian, haunted by dreams, is travelling aloing the coasts with his cousin Robert, Silverhair, and the mute boy, Piper, to rally defense against the reivers. In Los Osos they join in a ritual to call the dolphins to drive fish in from the sea. One of the dolphins has a rider. It is Rana, with the Sea Star blazing on her breast and the glory of the sea in her eyes.
With evidence that Caolin, with his Elayan background, is behind the raids, Julian and his companions set sail for the Great Bay to raise a navy to fight them. On the way, they are attacked by pirates, and Julian uses the Sea Star to summon–but not compel–the sea otters to their aid. When Julian comforts Rana, sick with reaction to the violence, he realizes that he loves her, and that her experiences with the pirates have left her unable to accept a man’s love. Involving the otters comes perilously close to misuse of his power, and the Guardians of the Sea summon Julian to the Floating Island to be judged. Because he only used the Sea Star to request the otters’ aid, not to force it, he is acquitted, but first he must undergo the initiation of the Sea, in which he experiences the cycle of water from rain to ocean and back again.
Back in Seagate, Julian gathers ships and learns seamanship and naval warfare. Rana struggles with conflicting feelings about her sister’s pregnancy and sexuality in general. On the island, Frederic recovers slowly, falling deeper in love with Ardra. Caolin disguises himself as a healer and drugs the prisoner, seeking to win Frederic’s soul. Julian tries to reach his mind in trance, but is repulsed by Caolin. Rana begins to heal as she uses the Sea Star to help her sister through a dangerous childbirth.
At last the Westrian fleet is ready. Julian sails out of the Bay to challenge Ardra. A strange fog ends the first engagement after a bloody battle. The Westrians retreat to the lagoon of Longbay Tomales Bay, near Point Reyes), where Rana’s brother-in-law dies. Horrified by the idea of another such battle, Rana calls the dolphins to take her out to Ardra’s ship to rescue Frederic.
On the ship, Ardra has decided to release Frederic herself when Caolin enters the cabin, taking one shape after another until he reveals himself as the Blood Lord, and the man who fathered her upon an Elayan princess. Ardra is horrified to learn that she has been serving his purposes all along. When she defies him, Caolin strikes her down. But when he leaves them, Rana gets there, and she and the dolphins bring both Frederic and Ardra away.
The raiders have lost their leader, but Caolin puts on her shape to continue the battle. Julian senses a great storm coming. He sails out to face Caolin as the others run for the shelter of the Bay, and the battle becomes one of sorcery, but Sea Mother (in her shape of a great Octopus) rises to counter the Kraken Caolin has summoned. Then the storm arrives, and Julian must call on the elementals of the sea to keep them afloat until it ends.
The Westrian ships escape the storm, but it devastates the enemy. Caolin is washed ashore and creeps back to the safety of the Red Mountain. The Westrians send the dead of both sides out to sea on burning ships, and Julian takes Ardra into the service of Westria. The next morning, Julian and Rana row out on the Bay and Rana calls the salmon to begin the cycle of life anew.