CASTLE AND BECKETT HAVE TO LOCK LIPS TO GET CLOSE ENOUGH TO CAPTURE A KILLER, ON ABC'S "CASTLE"

Max Martini ("The Unit") Guest Stars

"Knockdown" - Old wounds are reopened when the retired lead detective on Beckett's mother's homicide case contacts her with new information, but then is gunned down right in front of Beckett before he can tell her what he knows. The investigation into his death leads back to a decades-old conspiracy that may hold the answer to who was behind Beckett's mother murder and why. With the stakes and emotions running high, Castle and Beckett take their partnership to the next level, on "Castle," MONDAY, APRIL 25 (10:01-11:00 p.m. ET). Max Martini guest stars. (Rebroadcast. OAD 1/24/11)

"Castle" stars Nathan Fillion as Richard Castle, Stana Katic as NYPD Detective Kate Beckett, Susan Sullivan as Martha Rodgers, Molly Quinn as Alexis Castle, Ruben Santiago-Hudson as NYPD Captain Roy Montgomery, Tamala Jones as Medical Examiner Lanie Parish, Jon Huertas as NYPD Detective Javier Esposito and Seamus Dever as NYPD Detective Kevin Ryan.

Guest Cast: Max Martini as Hal Lockwood, Joel Polis as John Raglan, Ajay Vidure as CSU tech, Brian Goodman as Gary McCallister, Jonathan Adams as Vulcan Simmons, Scott Paulin as Jim Beckett.

"Knockdown" was written by Will Beall and directed by Tom Wright.

"Castle" is broadcast in 720 Progressive (720P), ABC's selected HDTV format, with 5.1 channel surround sound. This program carries a TV-14,L,V parental guideline.

For more information on "Castle," visit ABC.com. Viewers can also follow the show via http://facebook.com/Castle and Twitter: Castle_ABC