Together or not at all. THE DIFFERENCE

The dead don't sing in Nereth Bay. They wait. Mara's been hiding in the tide tunnels for two years-wild magic, no coven, no one to rely on but herself. When a storm surge brings a drowned boy to the grate where she's made her home, every survival instinct says run. She doesn't run. Elian Thorne was dead for three days before Mara pulled him back. Now he's breathing, but wrong: the water in his lungs won't leave, the dead whisper in his sleep, and the magic that binds them together is changing him into something the covens will do anything to destroy.
Their only refuge is the bone cathedral-a place built from the remains of witches the covens forgot. Its keeper, Anya, has waited three centuries for a love she lost to the deep harbor. She has a deal for Mara: retrieve those bones, and the cathedral's protection is theirs. But the harbor holds more than one woman's remains. Something ancient sleeps in the deep. Something lonely. Something that's been waiting even longer than Anya.
And it's starting to wake.