‘Citadel’ Episode 4 Recap & Ending, Explained: Is Mason Who We Think He Is?

In the last episode of Citadel, we were made to believe that Nadia is the spy setting things on fire, so to speak. We also learned that Kyle’s wife, Abby Conroy, was actually Anders Silje’s “love”, one who he thought was dead, but Bernard has used her as leverage to keep his brain intact. Let’s find out what happens next in Citadel


Spoilers Ahead

What Happens In Episode 4?

We are coming to the realization that Mason might’ve caused the big mess he is in currently only for the purpose of “saving” Nadia, but why? We need to return to the time before the Citadel fell. A new mission is at hand, and somebody needs to infiltrate the Silje brothers’ facility so they can find the “Oz Key,” which is essentially a hacking device. The twins plan on using it in Amsterdam (not quite sure for what reason; probably the usual drug dealing, money laundering, etc.), and Citadel must save the day. Nadia brings in her friend Celeste to do the job because she can have one of the brothers fall in love with her and get what they need. Celeste and Nadia seem extremely close, as Nadia says she trusts Celeste with her life. Nadia owes Celeste because she saved her life once.


In the present day, Nadia and Mason fight their way to save Carter. Nadia saves the day, but a surprised Carter is more afraid to head out with them than stay where he is. Back in the day, Mason gave Celeste a breakdown of the Silje twins. According to Mason, Anders is the brain, and Davik is the muscle of their operation, so Anders is the most dangerous of the two. Celeste’s mission is to make him fall in love with her and get to the Oz Key so Citadel can have it. Mason believes a good spy needs to be honest and only tell the truth. This shows a big part of who he is as a person—someone who is capable of forgetting himself in the mission, maybe because he has nothing to lose. But now, things are different; he has Nadia. Celeste knows she is up to the task, and Nadia believes so too. Mason is reluctant, but she is sent into the mission looking like a new person (I’m not quite sure how platinum blonde hair is such a makeover, but we’ll go with it).

Celeste introduces herself as Brielle to Anders and is quite quickly successful in her mission to get the guy to fall in love with her. She soon begins to live with them and sees every little thing the twins are working on. It is possible that Celeste actually fell in love with Anders, but unlike what Mason predicted, it doesn’t seem like she forgot what she was there for. But, soon, things look a bit wonky for Mason because Celeste disappears off the radar for three months. Without getting back to him on what she’s finding, Mason is losing patience and trust. According to him, Celeste may be behind the Oz Key because she is trying to save her twin brother from a gambling debt. Her brother and her are very close, and the easiest way to save her brother from some dangerous men would be by selling the Oz Key to the highest bidder, along with Citadel secrets.


Just when Celeste was about to escape with the Oz Key, Mason sent in an ops team to bring her out of there. They lost the Oz key, and there were many casualties in the process. Davik was supposed to be caught along with the key, but he managed to escape as well. The key that was found was the fake one that Celeste had replaced the real one with while stealing it. Only Anders was captured. Now, Mason interrogates Celeste to figure out what really happened and even uses her brother as leverage. Nadia thinks he’s going too far and supports her friend till the end. She doesn’t believe Celeste has done anything wrong and will not allow Mason to go any further and make things worse for her. Celeste wishes she hadn’t taken the mission in the first place, but Nadia requests Grace, their head, to bring Celeste out of all this and take her to a safe house.

Why Does Mason Backstop Celeste?

According to Mason, the only way to save Citadel is to backstop Celeste (the same procedure applied to them eight years later by Bernard after the train blew up), but at this point in time, it is just an experiment, and there’s no guarantee it is a safe procedure. Grace, the commander, doesn’t like the idea, but Mason convinces her by calling Celeste a mole, which puts Grace’s reputation on the line. Celeste is a Tier-one spy, meaning she has all of Citadel’s secrets locked in her memories. The backstop will wipe it all out. They give her the excuse of a new procedure that will reshape her cornea and fingertips so that she can live as another person and hide until things are safe for her to come back out once Davik is captured. Bernard is the guy who helps Mason set up the secret backstop procedure, but Mason also wants Celeste’s vial destroyed. Bernard tries to convince Mason that destroying her memories permanently would be something that could ruin Mason’s life permanently too, but Mason is certain she is the “mole” and needs this done. But why is Mason going so far?


Carter knows what’s really happening with Mason. It was Nadia who gave a secret order to the ops team and wiped the server so no one could know it was her. She is the real mole, but Mason is protecting her. We can’t really tell why, but maybe it’s because he’s in love with her. We already know Mason doesn’t lie, so it’s possibly his real feelings that are making him act out of character. Celeste had to take the blame for Nadia’s actions (or that’s what we think for now). Ironically, the new life Mason has invented for Celeste is the one he currently lives in with her and their child, Hendrix. Citadel Episode 4 ends in the present day where Carter tells Mason and Nadia, he won’t go with them because Nadia is the reason all of this started in the first place. 

Final Thoughts

Priyanka Chopra fights like a seasoned action hero, even though she hasn’t had much chance of doing sequences at such a scale before! I love watching her dance her way through those combat sequences. Hopefully, we get some real secrets in the next episode and maybe have some tables turned towards Mason and not Nadia this time around. Who is the real mole? Bernard has something to do with it. Or maybe, this whole time, Nadia and Mason have been working together to bring Citadel down.


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Ruchika Bhat
Ruchika Bhat
Ruchika, or "Ru," is a fashion designer and stylist by day and a serial binge-watcher by night. She dabbles in writing when she has the chance and loves to entertain herself with reading, K-pop dancing, and the occasional hangout with friends.

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