Sergeant Nix Marr has spent the last four years trying to leave the past where it belongs: buried at the bottom of the ocean, deep within the mines that drowned her best friend. So, when her royal flame, Kessandra, comes begging for her help investigating a massacre, Nix refuses. Vehemently. But Kessandra always gets what she wants. Aboard a luxurious submersible, Kess and Nix are drawn closer together the deeper they dive. But as dangerous as their attraction is, it’s not the greatest threat onboard: a deadly illness has emerged that drives its victims to extreme violence. When another royal is brutally murdered, it becomes apparent the disease has spread—and no one on the submersible is safe. Suddenly, survival hinges on trusting each other, which would be a hell of a lot easier if Kessandra didn’t keep lying. Injured, fighting for their lives, Nix has to decide if she can trust Kessandra again… and what she’ll lose if she does.