CBS' hit police procedural drama TV series "NCIS: Los Angeles" season 7 episode 18 "Exchange Rate" proved once again how valuable Anna is for the team.

The show opens up with a prisoner being transported to a safe house. The man was able to make his escape with a syringe that was left under the chair he was seated in. He grabs the item and stabs the agent on the neck and makes a run.

The first suspects of the crime were obviously those who prepared the safe house. Their investigation leads them to discover that Anna was a recent hire of the firm that took the job. It was also found out that she has visited Pena, the prisoner in question, while the latter was still incarcerated.

The group quickly turns their attention to Anna's father, Arkady Kolcheck. The reformed Russian spy claims innocence of the recent incidents, adding that he hasn't seen his daughter for a long time. It turns out that he's actually lying.

Kensi and Deeks did their homework on Pena's case. It was found out that there have been some anomalies in his arrest and that the DOJ attorney was only forced to make the decision.

All the pieces of the puzzle finally merge when Anna reveals that she's actually working for Hetty in this mission. As detailed by the operative, she wanted to win the trust of Pena into believing that she's a Russian attaché. They were supposed to meet with Anna's big boss, played by Callen. As it turns out, Pena is actually a Russian spy.

In the upcoming installment of the series, the synopsis from The Futon Critic said that fans might see Deeks and Kensi finally having a family of their own. The summary of the episode titled "The Seventh Child" meanwhile relays that CAllen and the team will be racing against the clock to save a child from imminent danger.

"NCIS: Los Angeles" season 7 airs Mondays, at 10 p.m. on CBS.