Here's the official guide of NCIS: Los Angeles season 4 episode 18 "Red". This episode airs on Tuesday, March 19 on CBS.
CALLEN AND SAM JOIN THE NCIS: RED TEAM WHEN A NATIONAL SECURITY CASE IN LOS ANGELES IS LINKED TO A MURDER INVESTIGATION IN IDAHO, ON PART ONE OF A TWO-PART EPISODE OF NCIS: LOS ANGELES --
Guest Stars Include Kim Raver as NCIS Special Agent Paris Summerskill
John Corbett as Roy Haines
Scott Grimes as NCIS Special Agent Dave Flynn
- When a murder weapon in Idaho matches the one used in a national security case in L.A., Callen and Sam fly to the crime scene to join NCIS: Red, a mobile team of agents who live and work together as they solve crimes in various locations.