WARNING: This article contains spoilers for the finale of NCIS season 18. Read at your own risk.

NCIS season 18 recently aired its final episode and sees Emily Wickersham leaving her role as Ellie Bishop. There have been clues that the character is leaving the police procedural drama, but her exit became one of the major happenings in "Rule 91."

NCIS season 18 wrapped up with the unexpected departure of Bishop, who has been part of the series since season 11. In her final episode, the character left in a shocking twist and it was something connected to what happened to her in the past.

Bishop revealed that she was the one who leaked a confidential NSA file a decade ago so she could go undercover as an NCIS agent. She is actually working for Odette (Elayn Taylor), who helped her framed everything up to make it look more convincing.

In the final moments of the episode, Bishop locked lips with Nick Torres (Wilmer Valderrama), the only member of the team who knows about her plan. Then, she bid goodbye to him and told him that she will be gone for a very long time.

Following her exit in NCIS season 18, Wickersham shared a photo on her Instagram account, confirming that she's now "hanging the hat and jacket up." The actress also thanked the cast, crew, and CBS after working with them for almost eight years.

Meanwhile, the reason why Wickersham departed from the police procedural drama hasn't been revealed. Right now, her exit is something that will impact the remaining character, most especially Torres. The two do have feelings for each other but weren't able to start a romantic relationship.

Wickersham's exit also comes not long after the departure of Maria Bello as Jack Sloane, who left the series in the current installment, as well. Since the series lost two cast members, new faces might be joining the department in the already-renewed season 19.

One of the notable names is Katrina Law's Jessica Knight, the only surviving member of REACT. The character first appeared in the last two episodes of NCIS season 18, wherein she asked the team to help her get justice for what happened to her colleagues.

Some speculated that Law might be promoted to a regular role in the next chapter. The team lost an agent, so they need someone to fill the role. Jessica Knight's skills also proved to be essential to the department, leading to Leon Vance (Rocky Carroll) giving her an opportunity to work with them.