I haven't worked it out yet, but it will probably be about a murder that takes place in a small coastal town similar to the one in which I live. Perhaps the victim will be a teacher at the regional high school... The homicide detective assigned to the case will be an undiagnosed bipolar, and this will sometimes complicate and sometimes enhance his abilities to solve the case, depending on his or her mood at the time. Eventually he gets a diagnosis and treatment, and he discovers that losing the manic side of his personality prevents him from making the brilliant deductions that helped him solve previous cases. So, while the book will primarily be a murder mystery, it will also serve as a informational account of bipolar disorder itself.