Having grown up in San Francisco, Calder Brumen is drawn to the ocean, and he's spent his life trying to capture the beauty of the Pacific on canvas. Over time, he has become obsessed with painting the image of a dark haired mermaid named Gaire, and Calder struggles to explain his devotion to these portraits to his best friend. When Calder finds sandy footprints leading to the edge of his bed, he suspects that the haunting siren is real.

Pursuing the truth, Calder is dragged into a murderous, underwater plot that could destroy them all. And he must choose – is the possibility of a lifetime with Gaire worth risking death for himself and everyone he loves?