Evan Carter came to study mermaids, never expecting to become the prey of a deadly Siren named Opal. After she kidnaps him and forces him to swallow a mysterious pearl, his body begins to transform. Trapped in her underwater lair, Evan must face a terrifying truth: he may never return to the human world. But as their dangerous obsession deepens, the line between captor and mate begins to blur. Will he escape the Siren who claimed him, or surrender to a love more dangerous than the ocean itself?