The CIA and BND make a play.
Saul accepts that Alison is a double agent. He and Carrie make a deal with the Germans to unmask Alison. Saul is using his personal relationship with Alison to set up surveillance on her. Alison is being followed on her way to the Russian safe house where is arrested. There is an attempt on Quinn's life.
Peter is heavily chained and scheduled by Dr. Aman Aziz as human guinea-pig for the Sarin nerve gas he discovered. he manages to convince his guard Qasim, the Jihadist emir's somewhat naive nephew, to learn about the horror it means inevitably to innocent German civilians as practiced by Assad in Syria, but by the time Qasim tries to free him, it's too late, he can only inject peter with atropine, which may lessen the effect. Carrie's evidence finally suffices to convince that Alison, whom she still ignored being his lover, is the mole and must be in league which the Russians. They convince near-discredited German secret service officials and equally reluctant Dar Adal to set up an elaborate trap. Allison is bugged by Saul, made to believe he's getting Israel political asylum and that she'll be exposed by a Russian defector and arrested while meeting Ivan Krupin, but manages to make Dar consider her claim that Ivan is her priceless double agent.
- Carrie comes to Saul through the Israeli diplomat Etai Luskin. He is still skeptical about Allison as Carrie explains she was working for the Russians. Saul says it can be catastrophic to have had a Russian spy inside their Europe operations for 10 years.
The van comes to an abandoned building, Quinn is taken through, he sees chemical canisters and pressure tanks being worked on. He is bound into a small room. He tells his guard, a nervous Syrian named Qasim, that the others are making sarin gas.
Saul and Carrie meet with Astrid and her BND bass, they discuss how to entrap Allison with enough evidence. This will not be sanctioned by Langley, the Germans agree to listen.
Qasim watches internet video of a previous sarin gas attack.
Saul goes to Allison's apartment. He says he is going to Tel Aviv in the morning and wanted to say goodbye.
In the middle of the night as Allison sleeps Saul goes and uses a toolkit to put a chip inside Allison"s purse. He also copies her phone memory, then returns to bed.
Wasim is wandering around, another man brags about the design of the sarin test chamber, they have atropine injectors in case of a leak. The American will be a test subject.
The Germans meet Allison and Dar and say they have a high ranking Russian defector who wants $5 million and to live in Boca Raton. Dar agrees to the terms as Allison is deep in thought.
Back in her office Allison texts someone as Saul and Carrie watch on a monitor. The text conversation is a coded reference to restaurant plans.
Qasim brings Quinn some water and food. The Syrian thinks the gas will not be used if the UN recognizes ISIL. Quinn tries to convince him otherwise and to get rid of the DF chemical.
Astrid, Saul and Carrie continue to watch Allison, on hidden camera they see her have sex with a boyfriend. Saul leaves the room as Carrie learns from Astrid about Saul and Allison.
Qasim is thinking; at night as others sleep he goes to the chemical room, a blue drum is empty. He tries to enter the test chamber, it is locked.
Allison sits alone at a cafe. Astrid meets her, she says the Russian needs an accelerated schedule, he is spooked. The Russian says the CIA has been compromised, and has evidence of material passed to the SVR. They are bringing him to Hamburg.
Allison calls the office and books a ticket to Copenhagen for later. She calls someone else but only only makes some beeping code noises. Then grabs a taxi. Inside she dismantles her phone, but they still have the purse transmitter. A the train station they continue to watch her on camera. She boards a commuter train, then gets out and goes to another. Astrid thinks she is going to Potsdam.They watch her leave the train. She gets into a car and drives off. Past farm fields she drives into the country and to a wooded area. A drone continues to watch her as she gets past a gate. The drone feed is lost, the area is being jammed. They recover video and see Ivan Krupin greet Allison and they enter a large countryhouse. Allison says a Russian mole is coming, Ivan says it is impossible. They then realize she was setup as German special forces attack the compound. Allison plans a story.
Ivan and Allison surrender to the Germans.
Dar is debriefed by Saul and Carrie. Dar then goes to the interrogation room. Allison is combative and tries to say Ivan has been her agent, not the other way around. Dar seems to have some doubts.
Quinn is taken to the test cell. Qasim signals and secretly gives Quinn an atropine shot. Quinn is locked inside and the gas valves are turned on. The jihadis watch behind a glass window as Quinn begins to twitch and shake, then collapse.