Lonely Hearts is the 15th episode of NCIS Season 17 and also the 393rd episode of the entire NCIS series.
The lead suspect in an NCIS murder investigation is a woman Gibbs' friend, Phillip Brooks, met on a dating site while Sloane has a secret admirer on Valentine's Day.
- Bishop discovers that Director Vance is on a dating app.
- Gibbs' friend Phil is discovered to be dating.
|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.|
|Eleanor Bishop||Emily Wickersham||Special Agent for the NCIS Major Case Response Team.|
|Nicholas Torres||Wilmer Valderrama||Special Agent for the NCIS Major Case Response Team.|
|Jacqueline Sloane||Maria Bello||NCIS Forensic Psychologist.|
|James Palmer||Brian Dietzen||Chief Medical Examiner for the Major Case Response Team.|
|Kasie Hines||Diona Reasonover||NCIS Forensic Specialist.|
|Leon Vance||Rocky Carroll||Director of NCIS. Despite being credited, Carroll doesn't appear in this episode.|
|Donald Mallard||David McCallum||NCIS Historian. Despite being credited, McCallum doesn't appear in this episode.|
|Phillip Brooks||Don Lake||Navy captain.|
|Stacy Gordon||Daphne Zuniga||Navy commander.|
|Tom Logan||Andy Comeau||M.P.D. detective and a serial killer.|
|Mary Talbot||Brynn Thayer||Sheriff.|
|Matthew Duques||Brian Ames|
|Sloane Jackston||Desi Dennis-Dylan|
|Molly||Caroline Whitney Smith|