Dr. Morgan Snow is a well-known sex therapist with a prestigious clinic devoted to the psychology of sex. One of her patients, Cleo, is a beautiful, cultured prostitute who runs her own call-girl business. Cleo has been coming to Dr. Snow because she's fallen in love, but is unable to have a healthy sexual relationship. One day, Cleo arrives with a manuscript for a tell-all book....and then disappears. A serial killer has been at work in the city, and Detective Noah Jordan turns to Morgan Snow to find out more about the psychology of a sexual murderer. Both Morgan and Noah suspect there is a link between the serial killer and Cleo's sudden disappearance, and work together to find her - before it is too late.