After years of learning how to manage her bipolar disorder, Emily Firestone finally has it under control. Even better, her life is coming together. Emily and her boyfriend, Paolo, go on a weekend sailing trip. But when she 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. 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.