It’s the episode that Firefly/Chuck fans everywhere have been clamoring for since the pilot episode of Castle. The one where Adam Baldwin guest stars. 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.
Watch Headhunters, Monday, April 16, at 10/9c, on ABC.