Photo Flash: First Look - Adam Baldwin Guest Stars on ABC's CASTLE, 4/16

On the April 16 episode of ABC's CASTLE entitled "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. The episode airs 10:01-11:00 p.m., on the ABC Television Network.

CASTLE stars Nathan Fillion as Richard Castle, Stana Katic as NYPD Detective Kate Beckett, Susan Sullivan as Martha Rodgers, Molly Quinn as Alexis Castle, Penny Johnson Jerald as NYPD Captain Victoria Gates, TAMALA JONES as Medical Examiner Lanie Parish, Jon Huertas as NYPD Detective Javier Esposito, and Seamus Dever as NYPD Detective Kevin Ryan.

Guest Cast: Adam Baldwin as Detective Ethan Slaughter, Michael McGrady as Brian Reilly, Michael Dorn as Dr. Carter Burke.

"Headhunters" was written by Alexi Hawley and directed by John Terlesky.

Get a first look at Adam Baldwin on CASTLE below!

Photo credit: Ron Tom/ABC