A tragic ending resolved a nail-biting cliffhanger on the latest "NCIS."

In "Double Back," the team tries to track down the terrorist Benham Parsa. The team discovers that the best lead to find Parsa is Parsa's driver, Bashir Malik. Bishop (Emily Wickersham) and Tony (Michael Weatherly) go on a fact-finding mission to track him down, which leads them to the NSA. 

Sofia Martinez was introduced, an NSA worker who flirts with Tony. She gives Tony the lowdown on Malik, and says the best way to find him is to track his communications with his sister. 

Meanwhile, McGee (Sean Murray) says Delilah's (Margo Harshman) condition is apparently improving after undergoing two surgeries. McGee is therefore cleared for work by Dr. Rachel Cranston (Wendy Makkena). Yet, McGee seems unable to concentrate on his work. He eventually reveals that the hasn't been honest with the team about her condition; Delilah is paralyzed. 

At episode's end, the search for Parsa goes cold. The team hunts down his driver by using the connection to his sister, but the only information he can provide is that he helped Parsa take a train to Miami, but he had planned to hop off the train before it reached its destination. 

When the show returns, the team will continue to look for Parsa, and McGee will deal with Delilah's permanent ailment.  

Showrunner Gary Glasberg told TVLine that he is "proud" of the difficult storyline. 

"Sometimes I walk into the writers room and I say, 'We're going to do something...,' and they look at me like I have six heads - and one of those instances was I wanted this bomb to go off, similar to some of the tragic stories that I saw after the Boston marathon," he shared. "I remember seeing a piece about a bunch of [female victims] who had managed to start to pull their lives back together again, and I wanted to try to capture some of that on our show. The intent is to show a really smart individual take control of her life and rise up after all she's been through. We're excited about the arc that character is going to face as someone in a wheelchair."

Glasberg also commented on a common fan complaint about the current season: why Tony is not keeping in touch with Bishop's predecessor, Ziva (Cote de Pablo). 

"A lot of people have approached me about the idea of not shutting the door entirely on [their staying in touch], and I'm not opposed to it," Glasberg said. "But it has to be done in a way where it feels organic to the storytelling and we're not just throwing in lines about Ziva here and there."

For example, Glasberg said, "If Tony's in a personal relationship or there's something significant happening for him and he wondered how she would respond, then maybe we can figure out a way to do it. It's a valid issue to bring up."

But, he said, the writers are "sensitive to him moving forward post-Ziva as the rest of the world is," because doing so "gives him the opportunity to grow and try things and meet people and move on."

Glasberg also said that Gibbs' mysterious second ex wife will probably be introduced in season 12. While fans have called for Mark Harmon's real-life wife, actress Pam Dawber, to play the role, Glasberg said it will probably not happen. "I have a feeling that's a tall order," he offered, "but it's worth a phone call."

On the 250th episode of this season, "My So-Called Life's" Bess Armstrong will guest star, but not as the new woman in DiNozzo Sr.'s life. 

"The woman in his life plays as a bit of a mystery," Glasberg said. "It's coming, but it's not cast yet." 

The next episode of "NCIS" will not air until February. The next episode will be called "Monsters and Men," and will air Tuesday, Feb. 4 at 8 p.m. on CBS.