Castle: 4x21
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 - 1Rise Sep. 19, 2011
4 - 2Heroes & Villains Sep. 26, 2011
4 - 3Head Case Oct. 03, 2011
4 - 4Kick the Ballistics Oct. 10, 2011
4 - 5Eye of the Beholder Oct. 17, 2011
4 - 6Demons Oct. 24, 2011
4 - 7Cops & Robbers Oct. 31, 2011
4 - 8Heartbreak Hotel Nov. 07, 2011
4 - 9Kill Shot Nov. 21, 2011
4 - 10Cuffed Dec. 05, 2011
4 - 11Till Death Do Us Part Jan. 09, 2012
4 - 12Dial M for Mayor Jan. 16, 2012
4 - 13An Embarrassment of Bitches Jan. 23, 2012
4 - 14The Blue Butterfly Feb. 06, 2012
4 - 15Pandora (1) Feb. 13, 2012
4 - 16Linchpin (2) Feb. 20, 2012
4 - 17Once Upon a Crime Feb. 27, 2012
4 - 18A Dance with Death Mar. 19, 2012
4 - 1947 Seconds Mar. 26, 2012
4 - 20The Limey Apr. 02, 2012
4 - 21Headhunters Apr. 16, 2012
4 - 22Undead Again Apr. 30, 2012
4 - 23Always May. 07, 2012