As we begin, we see Carrie and Saul meeting with Quinn's doctor, who informs us that Quinn is in a coma. Saul wants him awake so that he and Carrie can question him regarding the planned terror attack, which is just a few short hours away.
The doctor mentions a life-threatening procedure that could wake Quinn up, so Carrie and Saul order the doctor to begin preparing Quinn. What is one human life, when many others are at stake? What a horrible choice to have to make.
Elsewhere, Bibi's associate is planting the sarin device in a train tunnel.
Allison, meanwhile, is off to attend a diplomatic meeting at Dar's request, with her babysitter in tow. She collects a parking ticket off her windshield before taking off. Is it really a parking ticket? Of course not. It's a packet housing a thumb drive, which contains an audio file. Allison excuses herself to the restroom, and listens to the message that someone left for her.
When she exits the bathroom stall, a Russian intelligence officer is waiting for her and tells her to follow the instructions that she received in the audio file. The officer tells Allison to track down a professor from a local university, who is involved in carrying out the attack. Allison tells her that she can't get away to track him down without being caught. "I wouldn't worry about that. This will be your last assignment," the officer says.
Allison balks, and asks for a chance to prove her continued value. "You're damaged goods," the officer says, and tells Allison that Moscow wants the attack to go on as planned. The world needs an excuse to eradicate radical Islam, the woman says, and the attack will accelerate the timetable for making that happen.
She tells Allison that if she doesn't carry out her mission, Allison will forfeit the millions of dollars that she's earned and likely end up facing 10 to 20 years in a cell, either in CIA custody or in a federal prison.
At the hospital, the procedure to wake Quinn up is underway. It seems to be working, as he opens his eyes and raises his head. Carrie tells him that she needs to know where the attack is going to take place. Quinn tries to mutter something, but then vomits blood and his body begins to shut down. Carrie and Saul look on in horror as the procedure is aborted, and the medical team tries to salvage Quinn's life.
Bibi and his crew are preparing for the attack, but their trigger for the explosive device that was planted is not working correctly. Bibi gives it to Qasim, and tells him that he needs to take it to the professor that Allison was told about, to see if he can fix it. "You're trusting me?" Qasim asks. "I trust that you love your mother," Bibi says.
Back at the medical center, the doctor informs Carrie and Saul that Quinn has stabilized. His long-term prognosis is cloudy, but he's OK for the moment. Carrie tells Saul that given the fact that Quinn was treated for a bullet wound before he got there and that someone saved him from the sarin, that there is a disgruntled associate of Bibi's out there somewhere. She offers to track him down. Saul agrees, but tells her to check in with him every step of the way.
As Carrie leaves, Saul answers a call from Otto, who is upset that Faisal was arrested. Otto says that Faisal's lawyer can't access him, and that Saul didn't follow through on their agreement. "I'm talking about you and me, what your word is worth," Otto says. Saul agrees to see what he can do to rectify the situation.
After the call, Otto visits Laura and asks her to continue to stand down until the deadline for the attack has passed. Laura says that she will, but then calls Numan. Numan says that he stole the hacked documents back from Carrie's computer, and Laura asks him to release them should anything happen to her. "Go big, blow the damn lid off?" he asks. That's exactly what Laura wants, and she thanks Numan. She has a plan.
As Dar and the BND go over information, they learn of a link between the local technical university and Bibi's crew. The man who was killed in Qasim's place was a student there, which links the university, and the professor in question, to the planned attack. Allison offers to chase down that lead, and after some consideration, Dar agrees.
Carrie, meanwhile, is chasing down a lead of her own. She visits the home of her Hezbollah contact in Berlin, the man who promised to fight her forever, and asks for help in tracking down the doctor that saved Quinn's life. "Why should I help you?" he asks. "Honestly, I don't know," Carrie says, but tells him that he did the right thing once before. Given that her side is interested in stopping this attack, she says, and his side is keenly aware that this would be a bad time for world powers to rally together to fight Islam around the world, that their goals are in line. The man agrees, and gives Carrie a name.
As Saul goes about conducting a more humane interrogation of Faisal than the BND had planned, Astrid interrupts and brings him to a television. There, Laura is on a talk show, telling Faisal's story. She threatens to release the rest of the classified documents, unless she is allowed to speak to Faisal immediately.
Saul curses Laura under his breath, then he and Astrid return to the room where Faisal is being held. They find the room empty, and a window open, as they enter. Fearing the worst, Astrid looks out the window to the street below, where she sees Faisal's bloody, twisted body. "Our Laura Sutton problem just got worse," she says, while Saul sits down, looking defeated. "You deal with Laura Sutton. I think I've had enough for one day," Saul says.
Qasim arrives at the professor's home, and gives him the trigger. As the professor tries to fix it, Qasim asks him whether he has doubts about what they're doing. The professor says that he is acting to enact revenge on Germany for supporting Israel, not out of devotion to any Islamic faith. "I'm an atheist," he says.
A knock at the door interrupts them, and the professor sends Qasim away without fixing the trigger. He says that Bibi must manually activate the device, then hurries Qasim out through a back door. Allison and Conrad, her babysitter, are at the door. Allison alerts the professor that his student was found dead, and says that she's there to question him.
She notes that the professor has expertise in an area that would be helpful in carrying out the biological weapons attack, and orders him to tell her what the target is. The professor balks, and Allison asks Conrad for his gun. Conrad hesitates, but hands it to her.
Allison demands that the professor reveal the target and gives him a countdown. When the countdown ends, she turns the gun on Conrad and kills him. The professor then reveals the train station as the target, but Allison isn't done. She draws her own gun and fires three shots, killing the professor. The entire room is a bloodbath.
Allison calmly stages the scene to make it look as though there was a struggle, then calls Astrid. "Astrid, help, I've been shot," she says, then hangs up. She raises her weapon to her shoulder, aims, and shoots herself, then places the gun in the professor's hand. She lays down on the floor next to Conrad, and writhes in pain. Astrid and a team of police arrive at the crime scene, and Allison tells her that the airport will be the target of the attack.
She is absolutely shameless, isn't she?
Carrie reaches Dr. Hussein's house and asks him about Quinn. "To see him on television like that? the world has truly gone mad," the doctor says. After some discussion, he agrees to show Carrie Qasim's old apartment. From the apartment, Carrie calls Saul. She tells him that she found a ton of information about the train station, and tells him that's their target. Saul tells her that she's wrong — the airport is the place and it's being evacuated right now. "Saul, are you sure it's the airport?" Carrie asks. "It damn well better be," he says.
We see Qasim shaving off his beard and being told to hurry, because it's time.
Carrie grabs a photo of Qasim and Bibi and takes off for the train station anyway, while Saul finds out where Allison is being treated and goes off to question her as to the validity of her information. Allison answers a few of Saul's questions, but the session is cut short. Allison won't be having surgery until after the deadline has passed, but the medical team needs to treat her wound, buying her a few minutes before Saul's interrogation continues.
As Carrie paces the train station, then heads off to the security office there, Qasim and the rest of Bibi's team begins closing and locking gates, trapping people in the station. Carrie spots Qasim, and tries to text Saul, but her phone doesn't have signal. She corrals a bystander and asks her to take her phone above ground to get the message out.
Qasim reaches his designated gate and begins closing it, but after seeing the faces of some people that would have been trapped there, he loses his nerve and walks off.
Carrie rushes to the designated stop and sees a crowd gathered there. A passenger tells her that someone just jumped onto the tracks and ran into the tunnel. So, Carrie draws her gun and charges into the tunnel.
Just then, Saul receives Carrie's text message. He runs into Allison's room, but Allison has vanished.
This was an awesome episode, packing the best of Homeland into one of the most intense, dramatic hours of television all year.
I think that Allison's motivation was expertly explained by the writers here.
Eleven down, one to go.