With tensions rising between Castle and Beckett, Castle finds himself a new partner -- Detective Ethan Slaughter (guest star Adam Baldwin, "Firefly"), a tough and colorful cop from the city's gang unit. But Castle gets more than he bargained for when Slaughter shows him a grittier side of police work that puts Castle in the line of fire like never before
Keywords: criminal-consultant , criminal-investigation , female-detective , homicide-detective , new-york-city , novelist , police , police-procedural , writer , watch-series-online