Author Richard Castle joins NYC Detective Kate Beckett to help solve the case of a serial killer who is reenacting murders from Castle's novels; Castle becomes very intrigued with the murders and continues to shadow Beckett, much to her chagrin.

Castle and Beckett's first case together is to solve the mystery of the death of a young nanny inside a laundry room; their investigation leads to a twisted world of play dates between babysitters and their employers; Castle considers Beckett's character while continuing to write for his "Nikki Heat" series.

Castle and Beckett investigate the case of a rich teenager found dead of a gunshot wound in a boat in Central Park lake; Castle becomes more involved in Alexis' life and make sure she is on the right track.

Castle and Beckett investigate the death of an NYC councilman who was running for re-election; Castle's latest book hits the stands and his mother offers only negative reviews.

A woman's frozen body is found at a construction site leading Beckett and Castle to reopen a cold case; the case becomes more muddled when they find the husband of the deceased woman was murdered a year ago; the gruesome investigation stirs old memories from Beckett's past.

Following the ritualistic killings of two people, Beckett and Castle enter the world of Vodun and find out the suspect is looking for forged travel papers hidden in a counterfeit bag sold to an unsuspecting woman; Castle's ex-wife, Meredith, decides she is moving back to New York.