Deep in Germany's Liepnitzsee Forest, Max Ruddiger wires a bomb into a sleek BMW. His client, gorgeous Gina Zanetakos arrives to witness the car's explosion as proof of concept, then orders a radioactive version of the car bomb, complete with caesium 137, to be delivered in 36 hours.
Back in D.C., Liz and Tom stand over the box in the floor, arguing. Livid, Tom demands to know what's going on and denies any knowledge of the box's contents. Explaining the gun was used in the murder of defecting Russian agent Victor Fokin, Liz shows Tom the surveillance photo placing him at Angel Station. Tom points out that all the bad stuff in their life comes from her job; if Liz thinks he's guilty of something, she should call the FBI. Despite Liz's warning that the FBI will pick apart their lives, Tom prevails upon her to make the call.
By the time the hood is lifted off his head, Tom is incredulous to learn the true nature of Liz's job. Before Meera sequesters him in an interrogation room, Liz pulls Tom aside. Everything will be okay as long as he tells the truth. Elsewhere, Red and Grey survey Rembrandt's famous stolen painting "The Storm on the Sea of Galilee." Red promises his client, Hakim, the painting will be in hand well before the wedding. Just then, Grey's phone rings with news about Liz, whom Cooper has put on leave and sent home.
Liz proceeds to a bench in Lafayette Park where Red delivers news on the corporate espionage front. He recalls a case where seven people were killed by an over-the-counter drug laced with poison, putting the drug company's market share in the toilet. Someone was hired to do that, someone like corporate terrorist Gina Zanetakos. If Liz wants to find out the truth about Tom, she's going to have to find Gina because... Gina is Tom's lover. Upset with Liz's forced leave, Red proceeds to Cooper's office to cut a deal, and it's not long before Cooper informs Meera and Ressler that Liz is back on the job.
Liz briefs the team on Gina Zanetakos, who entered the U.S. yesterday using the alias Shubie Hartwell. Resident FBI tech Aram has learned Shubie last used her credit card to purchase drinks at the Quay Hotel two hours ago. At the hotel, Gina is seducing a Turkish national named Nadeem Idris. When he hands over an unseen piece of paper, Gina stabs him in the neck with a syringe... and he's down. Gina quickly rips off her wig and makes the murder look like suicide, then slips out just as Liz and Ressler arrive. Thinking the coast is clear, Gina gets onto the elevator, but Ressler gets on shortly after her. Dropping her phone, she beats the crap out of him and leaves him unconscious on the floor.
Aram deconstructs Gina's phone, which reveals that she was in contact with The Hanar Group; more worrisome is a message regarding her plan to detonate a dirty bomb. Meanwhile, Tom tells Meera that he traveled to Boston for a job interview with Walter Burris, headmaster at the Rothwell School, whom he met at the Angel Station Hotel. After meeting with the real Burris, Meera shows Tom his photo - a man he's never seen before. Watching over surveillance cameras, Liz is sure Tom's being set up. Nevertheless, she checks the surveillance photo of Tom at Angel Station, only to find Gina in the picture.
Having gleaned Gina's address from her phone, the FBI breaks in. Liz quickly finds a hidden box much like the one under her own floor, filled with passports and surveillance photos. Notably there's a photo of Victor Fokin, which Liz takes to mean Gina may have killed Victor. That's when a tech proffers a photo of Tom found by Gina's bed. Ressler grabs the photo as evidence, advising Liz to protect herself. With nowhere else to go, Liz arranges a meeting with Red. Could he be manipulating events to ruin her life? One thing's for sure, Liz isn't sure she can survive without Tom. She needed Red to be wrong about him, and worse yet, his is the only shoulder she has to cry on.
Cooper discovers evidence of a payment Gina made to bomb expert Ruddiger. The FBI needs Red to find him, so they need Liz, who needs to find Gina to clear Tom; it's a sticky web. Liz finds Red yelling over the phone at his contact, Hakim, who has diverted payment on the purloined Rembrandt to New Orleans - unacceptable! Red knows Ruddiger, a big drinker. It's not long before Red's pouring whiskey for Ruddiger in Germany, plying him with the promise of a big money job. Ruddiger admits his bomb is wired into a car that is set to contaminate a five-mile radius in 19 hours - he just doesn't know where. Promising none of this will come back on Ruddiger, Red asks him to call Gina to arrange a meet, then passes the location to the FBI.
The FBI converges on Gina in D.C.'s Central Park. Liz follows her into the women's room and winds up fighting for her life. Ressler arrives to shoot Gina in the nick of time, but Liz is furious. Gina is her only chance to clear Tom! And what about the bomb? Cooper and Ressler assure her that Gina is in surgery. In the meantime, a review of the evidence reveals that the Hanar Group's stock is in trouble, due to plummeting financials for their New Orleans port. Recalling Red's argument over payment diverted to New Orleans, Liz figures it all out. The Hanar Group hired Gina to bomb the Port of Houston, making their New Orleans operation the only game in the Gulf.
As Liz, Ressler and an enormous SWAT team descend on the Port of Houston seeking Gina's car bomb, Meera informs Tom that his girlfriend (Gina) has been shot - what does he know about the bomb? Tom knows nothing about Gina or her bomb, but his protests fall on deaf ears. Luckily, Liz manages to plug in the missing link - it was Idris who shipped the car bomb to Houston! The car is quickly located, but the bomb squad has no idea how to disarm it. Thinking fast, Liz proposes a plan to crane the car off the ship. With less than a minute to go, Ressler drives it into the Gulf, bailing out at the last second. The car explodes underwater, effectively neutralizing the radioactive contamination.
Meera and Ressler visit Gina at the hospital to offer a plea agreement. Gina admits to killing Victor Fokin, claiming Red hired her to do it. Desperate, Liz shows her a photo of Tom; lucky for Liz and Tom, Gina has never seen him before. Upon his release, Tom collapses into Liz's arms in the war room. Their ordeal is over... until Tom spots a photo of Grey on the evidence wall. Grey is the man who posed as Burris during his job interview at Angel Station! Certain Red set them up and planted the box in their home, Liz tells him they're through. Red insists he can only lead her to the truth; he can't make her believe it. "Go to hell," Liz says, slamming the door on her way out.