'NCIS': Ziva's Return Leads to Major Character Death After Devastating Twist

Ziva returned for the intense NCIS Season 17 fall finale, and the final scene will have us in shock until its return in the new year. The CBS crime procedural returned with a new episode Tuesday featuring the return of Cote de Pablo's beloved character, as she worked with the team to finish her undercover mission once and for all. The hour lead to a heartbreaking twist surrounding one of Gibbs' closest friends.

Spoilers ahead for NCIS Season 17, Episode 10: "The North Pole"

The episode began with Bishop (Emily Wickersham) meeting a man to retrieve a drive with intel for Ziva (de Pablo) at a club. It is later revealed that she was sent to do the mission by Ziva's associate Odette (Elayn J. Taylor), saying that Ziva cannot handle big crowds anymore. When Bishop demands answers about what is going on, Odette tells her it's safer for her not to know any details. Bishop refuses to hand over the intel and walks away to report back to the team.

Gibbs (Mark Harmon) helps Phineas (Jack Fisher) and his mom at their house when he gets a call to head to the office. Before he arrives The crew decides there has to be something going on with Odette, and find out Ziva's childhood friend has been captured.

Gibbs makes a stop on the way meets with Ziva in an alley, where she confronts him for interfering. They realize Odette went rogue and asked Bishop to do the mission without Ziva's consent. After confronting her friend, Ziva admits Odette was trying to protect her from having another anxiety attack.

After she agrees to take the team's help, Ziva reveals she thinks something is wrong with Adam. The drive Bishop got is connected to the man and it is imperative she gets it.

When Gibbs asks why it's so important, it is revealed through flashback that Adam was the one who helped Ziva fake her death in order to keep Tali safe during her undercover mission. The episode also reveals Ziva experienced her first panic attack after separating from her daughter. Adam then became a double agent in Sahar's organization, but their confrontation at the start of the season revealed his identity and put him in danger.

After Kasie finds the location where Adam is held, Ziva and Gibbs arrive to save him. He keeps saying Sahar, and reveals the woman they met first was a decoy and the real one is alive. The twist? She knows her! He passes out before he can say anything else and they struggle to find it, before they free up, the pair fall into a hole in the ground and pass out themselves.

Gibbs and Ziva wake and find themselves under the warehouse and trapped. The stress of their situation start to affect Ziva, but Gibbs calms her down getting her to talk about Tali. When they are free, they find Adam but he is dead.

Through flashback, it is revealed that Adam was in love with Ziva, which drove him to help her in her mission. Gibbs finds Ziva in the cabin and tries to convince her to call Tony and ask him for help. She refuses, saying she is trying to keep them safe. The conversation turns into an argument where she says she regrets killing her brother and starting all this drama so many years in the past.

When he leaves, she takes out a secret phone. As the investigation unfolds, Gibbs finds out that the real Sahar is actually Phineas' mom. When they arrive at her home, Phineas admits his mom sometimes leaves him alone at night to work.

Gibbs demands proof he was played before going after the woman. Phineas swears he has no idea where she is and asks Gibbs to make sure nothing happens to her. Ziva interrogate a suspect and his information leads her to Sahar. They have a violent encounter that the evil woman wins, leaving Ziva trapped. Sahar reveals she knows about Tali and that she will kill her once Ziva is dead. Gibbs, however, arrives just in time to kill the woman and save his friend.

Odette admits after the fact she involved the team because she knew Ziva would be too proud to ask for help. She also revealed she sees promise, and offers her "specialized training." Ziva reveals to Gibbs near the end of the episode she called Tony and had him and Tali hide in a secret location. She and Gibbs make amends, as Gibbs says he will never regret saving her. The episode ends with Gibbs walking to tell Phineas about his mother's death.

What will happen next? NCIS will return with new episodes Tuesday, Jan. 7 at 8 p.m. ET on CBS.