Michael Jeck suffers from severe dissociative identity disorder as a result of a series of traumatic incidents in his childhood. He has five separate and individual personalities-Kara, a brainy, intellectual woman trained as a medical examiner; Nick, an aggressive hit first ask questions later guy; Alex, the suave, sophisticated, educated man; Telly, a brainy teenager who is an expert with computers and technology; and Sara, a mute eight year old girl who creates mature, beautiful works of art to express herself.

Thanks to years of experimental psychotherapy, Jeck has managed to gain control over his five other personalities, not by suppressing them, but by living with them. He then uses their specific skills and talents to form a kind of think tank, capable of effectively solving complex and difficult crimes. In this way, he and his five personalities function as a unified whole, rather than individual parts-a truly gestalt personality.

Michael Jeck is now a special agent with the FBI and has garnered a reputation as an eccentric genius that can solve any case. Recently, however, he has been unable to crack a strange series of murders that appear to be completely different but also thinly connected to each other. Concerned with the lack of results, the Assistant Director of the FBI decides to assign Jeck a partner for the very first time.

Enter Grayson O'Neal, an FBI agent from the behavioral sciences division, whose mysterious past and strange eagerness to work with Agent Jeck causes a newfound tension amongst the normal "group" dynamic.

Together, Jeck and Grayson work together to solve the mystery of the serial killings, at the same time trying to come to terms with their respective pasts, and their uncertain futures.