Winter and Isidor are two sexy Siblin brothers that have been sailing the world searching for their father, Maren. They take their ship, the Singsong, through the dangerous Brecca Strait, where sirens have been singing to sailors and wrecking ships for over 200 years.

In the mouth of the strait is Nanine Island, where they find their father’s ship, the Wandering Eye. There, the brothers meet Soule, a beautiful red-haired siren their father adopted when she was a child. There, the brothers also learn that Soule is their anthata, a lifelong bond between a woman and two Siblin brothers.

Isidor and Winter take Soule to try to persuade the Siblin Council to recognize her as their anthata. But they are opposed by two Siblin brothers whose parents were killed by a siren. Winter and Isidor resolve to go back to the Brecca Strait to learn how to stop the sirens who are still wrecking ships.

Sailing in the Singsong, Winter and Isidor take Soule to Halit Island near the Brecca Strait, pursued by Havish and Leet. On the island, a flash flood comes. Winter is swept away. Isidor lies unconscious at the bottom of a deep fissure. Soule is alone with the brothers who have sworn to kill her, and the water is rising fast.