On the latest "NCIS: Los Angeles," the team hunted down a war criminal in L.A. while Kensi started her mysterious new assignment.

"Iron Curtain Rising," begins with the FBI sweeping a restaurant to find Anton Zevlos, a war criminal who was the mastermind behind Romania's human trafficking ring. The organization created false adoption papers for children and babies and used the children as organ donors. Zevlos disappeared after the regime fell.

Zevlos has a connection with Millionaire Charter, which is owned by someone who was in the KGB. Callen (Chris O'Donnell), Deeks (Eric Christian Olsen) and Sam (LL Cool J) briefly find him when he goes to the bank to try to get money, but he escapes after a shootout ensues.

The team then finds out that Zevlos was mostly likely going to leave on a fight for two to Costa Rica. Yet, Zevlos isn't near the airport. However, his accomplice, Banks, is on the plane, and he cracks when the team threatens to kill him by crashing the plane while they escape with parachutes.

They then track down Zevlos' lawyer/mistress, Carla, who has cashed out her bank account and chartered a boat for their escape. The team is able to catch and arrest them both. Zevlos is then sent back to be tried at a Romanian war crimes tribunal.

Meanwhile, Kensi (Daniela Ruah) arrives at a base in Afghanistan. Granger (Miguel Ferrer) shows up and tells Kensi that she is there to kill White Ghost, who is suspected to be an American working with the Taliban because the insurgents are using advanced combat strategies.

Viewers were also introduced to two new characters, Rachel Harris and Booker.

On the next episode, "Merry Evasion," the NCIS team will search for a motive when a senator's daughter is attacked. They will try to determine if the attack is tied to the senator's attempts to crack down on cyber warfare.

The synopsis further reads: "Deeks and Nell will partner up to help Sam and Callen bring the daughter to safety, and Kensi is going to receive the perfect holiday gift from one of her co-workers. Michelle Trachtenberg will guest star as Lily Lockhart, the Senator's Daughter. Other guest stars will include: Erik Palladino as Vostanik Sabatino, John Getz as Senator Lockhart, Troy Ruptash as Ludomir Susic, Antonio D. Charity as W&P Worker, and Roy Vongtama as Lance Witten."

Watch the promo below for "Merry Evasion," which airs Tuesday, Dec. 17 at 8 p.m. EST on CBS.