A red tide is rising. As the daughter of one of the mer-king's trusted advisors, seventeen-year-old Jade has great responsibilities. When her fiancé murders a naiad, plunging the underwater city of Thessalonike into uproar, tensions surge between the mer and the naiads. Jade learns too late that the choices she makes ripple further than she'd ever imagined. And as she fights against the tide of anger in a city that lives for scandal, she discovers danger lurking in every canal, imperiling her family and shattering the ocean's fragile peace. Can the city's divisions be mended before the upwelling of hate rips apart everything Jade loves?