For fans of B. A. Paris and Mary Kubica comes a propulsive, twisting psychological thriller that asks, How can you save someone else if you can't save yourself?

After years of learning how to manage her bipolar disorder, Emily Firestone finally has it under control. Even better, her life is coming together: she's got a great job, her own place, and a boyfriend, Paolo, who adores her. So when Paolo suggests a weekend sailing trip, Emily agrees—wine, water, and the man she loves? What could be better? But when Emily wakes the morning after they set sail, the boat is still adrift ... and Paolo is gone.

A strong swimmer, there's no way Paolo drowned, but Emily is at a loss for any other explanation. Where else could he have gone? And why? As the hours and days pass by, each moment marking Paolo's disappearance, Emily's hard-won stability begins to slip.

But when Emily uncovers evidence suggesting Paolo was murdered, the investigation throws her mania into overdrive, even as she becomes a person of interest in her own personal tragedy. To clear her name, Emily must find the truth—but can she hold onto her own sanity in the process?