Three Hearts is the 21st episode of NCIS: Los Angeles Season 5 as well as the 117th episode of the entire NCIS: Los Angeles series.
OSP investigate when an undercover NCIS agent is arrested after the team suspect that he's working for the smuggler he's supposed to have been investigating while Kensi and Deeks discuss things as she returns to the field since the Afghanistan incident.
- Despite their feelings for each other, Kensi and Deeks decide to remain friends.
- Deeks returns Kensi's knife.
- Deeks finally opens the Box that Kensi gave him in Red Part 1 (episode), but learns it contains a smaller box.
|G. Callen||Chris O'Donnell||NCIS Special Agent and the leader of the Office of Special Projects field team.|
|Sam Hanna||LL Cool J||A former Navy SEAL-turned-NCIS Special Agent with the Office of Special Projects.|
|Henrietta Lange||Linda Hunt||Operations Manager with the Office of Special Projects.|
|Marty Deeks||Eric Christian Olsen||A Detective with the Los Angeles Police Department and also the LAPD/NCIS liaison.|
|Kensi Blye||Daniela Ruah||NCIS Special Agent with the Office of Special Projects.|
|Eric Beale||Barrett Foa||Tech Operator with the Office of Special Projects.|
|Nell Jones||Renée Felice Smith||Tech Analyst for the Office of Special Projects.|
|Owen Granger||Miguel Ferrer||NCIS Assistant Director.|
|Paul Angelo||Daniel Henney||NCIS Special Agent.|
|Olivia Brunson||Emily Baldoni||Tyler Brunson's wife.|
|Tyler Brunson||Stephen Wozniak||Olivia Brunson's husband.|
|Guard 1 (Three Hearts)||J. Teddy Garces|
|Venice OG||Kaleti Williams|
|Venice Homie 1||Brent Gutierrez|