On the latest episode of "NCIS: Los Angeles," the team investigated an NCIS agent who is suspected of turning to the dark side.

In "Three Hearts," it's up to the NCIS team to figure out if Paul Angelo (Daniel Henney), an undercover NCIS agent, turned because of his 19-month deep cover with a smuggler who is in possession of something illicit.

It's obvious that Angelo cannot be trusted, and he readily claims to have turned Olivia. He eventually gives Hetty (Linda Hunt) the safe word, allowing the team to take down Brunson, Olivia and their men.

Angelo is then free to go, but his traitorous ways have consequences: his real name has been wiped from the public record, meaning he is permanently Angelo, his undercover persona. Also, as penance for his crimes, Hetty is able to call on him to do favors for the NCIS team.

Kensi (Daniela Ruah) and Deeks (Eric Christian Olsen) also discuss their relationship in the episode, because Angelo and Olivia's relationship reminds Deeks of himself and Kensi. Yet, Kensi assures Deeks that what happened between Olivia and Angelo has nothing to do with them.

Later, the two talk more about their relationship, and Deeks tells Kensi: "Contrary to hundreds of year of scientific evidence, I believe that raccoons do mate for life." With that, she takes down the box that has been sitting on her shelf for awhile, opens it and gives it to Deeks. But inside the box is another box, leaving the mystery of the box intact.

On the next episode, "One More Chance," "A 10-year-old girl Sam once provided protection detail for in Saudi Arabia goes missing, and he's convinced her disappearance is directly connected to the theft of software for a new unmanned-aerial vehicle being developed by her engineer father."

Also, in a future episode, executive producer Shane Brennan said that the contents of the box that Kensi gave Deeks will finally be revealed.

"That box gets opened," Brennan told TVGuide. "It's a lovely moment between the two of them."

However, he hinted that that moment could be ruined by the return of DEA Agent Talia in the season finale.

Watch the promo below for "One More Chance," which airs Tuesday, April 29 at 9 p.m. EDT on CBS.