Tabitha Slate used to worry about her grades or being the only Black girl in her engineering classes. Then she bumbled into the Wardein: the guardians who protect Seattle from its supernatural human hybrid and cryptid citizens hiding in plain sight. She joined them and swore an oath to perform her duty, even if it meant her life. But Tabitha has lost one of the best friends she ever made, and she blames the leader of the Wardein.

What's left of Tabitha's family is unraveling, an evil djinn with a score to settle is targeting her and her housemates, but Tabitha is on her own. The Wardein are busy with the biggest threat they've ever faced: Someone is trying to breach the Trench, the only barrier between the Puget Sound and a voracious horror nearly as old as the sea.

Tabitha's world is in pieces. Divided between loyalty and duty, she's afraid she will choose the wrong person to protect, the wrong family to abandon, and the wrong person to love.