Emily manages her bipolar disorder well enough to work as a moderately successful child psychologist, and is building a serious relationship with her boyfriend Paolo. When he wants to take her on an overnight sailing trip, Emily knows her medication, generous amounts of wine, and her attraction to Paolo will help her deal with her aversion to the water and forget the fact that she can't swim. But after a romantic night, Emily wakes up on the sailboat, completely alone, drifting through the waves. Her world is turned upside down as she becomes a person of interest while grieving Paolo, never getting answers or closure to what happened to him. He was a strong swimmer, and she cannot believe he simply drowned. With her personal and professional life in shambles, Emily attempts to find out the truth and clear her name, discovering a deeper and more dangerous plot than she ever suspected. Fueled by her own mania, Emily questions her own judgment every step of the way.