Third Wheel is the 4th episode of NCIS Season 16 and also the 358th episode of the entire NCIS series.
Gibbs’ quiet vacation at his remote cabin is interrupted by a surprise visit from Tobias Fornell and Navy Captain Phillip Brooks, as well as a call from NCIS asking for his help locating a robber hiding in the woods near him.
- Gibbs takes time off from NCIS and has McGee temporarily take over in order to blow off steam from his earlier role as acting director.
- It is revealed that Jack Sloane had a falling out with a old acquaintance from the FBI due to losing her car in a bet.
- The production code for this episodes indicates it was filmed before "Boom", but aired afterwards.
- Despite being credited, Rocky Carroll doesn't appear in this episode.
|Leroy Jethro Gibbs||Mark Harmon||Special Agent in charge of the NCIS Major Case Response Team.|
|Timothy McGee||Sean Murray||Senior Special Agent and second-in command of the NCIS Major Case Response Team.|
|Nicholas Torres||Wilmer Valderrama||Special Agent for the NCIS Major Case Response Team.|
|Eleanor Bishop||Emily Wickersham||Special Agent for the NCIS Major Case Response Team|
|Jacqueline Sloane||Maria Bello||NCIS Forensic Psychologist|
|James Palmer||Brian Dietzen||Medical Examiner for the Major Case Response Team|
|Kasie Hines||Diona Reasonover||NCIS Forensic Specialist; Abby's replacement|
|Leon Vance||Rocky Carroll||Director of NCIS|
|Donald Mallard||David McCallum||Chief Medical Examiner for the NCIS Major Case Response Team.|
|Tobias Fornell||Joe Spano||Former FBI Agent|
|Phillip Brooks||Don Lake||Navy Captain.|
|Isabel Monet||Kate Orsini||FBI Special Agent.|
|Anna Jenlowe||Emily Rose||FBI Special Agent|
|Muncie Tyson||Rich Ceraulo Ko||North Carolina State Trooper.|
|Kaitlyn Holcomb||Amielynn Abellera||Navy Lieutenant|
|Lovinder Prasad||Daryl C. Brown||Navy Commander|
|William Forman||Bo Kane||North Carolina State Trooper.|
|Horace Barnes||Ian Gregory||FAA Security Specialist|
|Susan Ottsley||Jill Czarnowski||NCIS Tech.|