Castle Season 4 Episode 21
Headhunters
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
4 - 23AlwaysMay. 07, 2012- 4 - 22Undead AgainApr. 30, 2012
- 4 - 21HeadhuntersApr. 16, 2012
- 4 - 20The LimeyApr. 02, 2012
- 4 - 1947 SecondsMar. 26, 2012
- 4 - 18A Dance with DeathMar. 19, 2012
- 4 - 17Once Upon A CrimeFeb. 27, 2012
- 4 - 16Linchpin (2)Feb. 20, 2012
- 4 - 15Pandora (1)Feb. 13, 2012
- 4 - 14The Blue ButterflyFeb. 06, 2012
- 4 - 13An Embarrassment of BitchesJan. 23, 2012
- 4 - 12Dial M for MayorJan. 16, 2012
- 4 - 11Till Death Do Us PartJan. 09, 2012
- 4 - 10CuffedDec. 05, 2011
- 4 - 9Kill ShotNov. 21, 2011
- 4 - 8Heartbreak HotelNov. 07, 2011
- 4 - 7Cops & RobbersOct. 31, 2011
- 4 - 6DemonsOct. 24, 2011
- 4 - 5Eye of the BeholderOct. 17, 2011
- 4 - 4Kick the BallisticsOct. 10, 2011
- 4 - 3Head CaseOct. 03, 2011
- 4 - 2Heroes and VillainsSep. 26, 2011
- 4 - 1RiseSep. 19, 2011
