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Previously on Mi-5
Adam (Rupert Penry-Jones) attacks a mugger and puts him in a coma, only to learn that he was an investigative journalist chasing the Tehran bombing story. In the episode's final minutes, Adam almost dies by Ana's (Agni Scott) hands, only to have Ros (Hermione Norris) save him and shoot two bullets into the troubled wife of the Iranian Special Consul. For more, read the full episode recap here.
This Week's Episode: "The Courier"
After yet another near-death experience, Adam returns to HQ looking just fine and dandy, if a little shell-shocked, and he immediately goes to Ros and apologizes for putting her in such a dangerous position. Harry (Peter Firth), meanwhile, has to pick up the pieces from their failed mission, as Iran has gotten their hands on nuclear triggers despite the United Kingdom and United States' best efforts to stop them with the fake codes they "secretly" sold to them. But the only way Iran could have known about the fake codes would be if there was a mole inside Mi-5. Richard Rolfe (Sam Graham) of the Joint Intelligence Committee promises that he will send his own men into Section D to search for any signs of secret surveillance, ignorant of the fact that Ros (and the anti-American group Yalta) are the culprits.
At headquarters, the team has their hands full with passenger manifests, knowing that if the nuclear triggers are heading to Iran today, it will be on one of three flights headed out of Heathrow. Suddenly, Jo (Miranda Raison) receives an anonymous e-mail.
"Fifty liters of dimethyl mercury are waiting to be released in your water supply. Unless the courier with the circuit boards reaches Tehran safely we will activate the device. Any attempt to disarm it will be monitored."
As Malcolm (Hugh Simon) points out that this toxin is enough to take out an entire city, Ros has a realization. Yalta is behind this, as she knows they are able to listen to everything going on at headquarters thanks to the small bug devices they had her plant around the offices. Distraught that she has potentially helped fuel a war, she leaves the office to meet with Yalta handler Sholto (James Laurenson) to express her grievances. Shrugging her off, he tells her to find the four bugs she planted, otherwise she's of no use to Harry. Or to them.
Going against protocol (i.e. get to Heathrow now!), Adam follows Iranian Special Consul Dariush Bakhshi (Simon Abkarian) to a restaurant and feeds Mi-5 audio surveillance of Bakhshi's conversation with a mysterious Russian. Connie (Gemma Jones) does her best to translate the conversation, and she hits on two words: "Courier" and "British." Of the three planes flying to Iran, 54 of the passengers hold a British passport, so the team gets started on vetting the potential suspects.
Back on schedule, Adam arrives at the airport and has a word with security. Since they can't let their enemies know that they're on their tail, lest they decide to release the toxin into the London water supply, Adam orders that all items must go onboard all three planes regardless of if they raise any red flags. But what he doesn't know is that, back at headquarters, Ros and Harry are engaged in a very serious discussion. Perhaps Bakhshi is their key to discovering who's transporting the nuclear triggers out of the country. Perhaps they should let Bakhshi know...that his wife is very much alive and in an Mi-5 safe house.
At the airport, Adam receives a call from Connie. Her translation was wrong. "It's not 'courier,' it's 'carrier.' It's not a British passport. It's a British flight." Specifically British Intercontinental 1505. As he makes his way across the terminal, Malcolm goes onboard in disguise and checks out the plane's diagnostics. Somebody has slashed the flame arrestors on both engines, and so if the plane hits turbulence or goes through an electrical storm, it will likely explode, a bomb that can go off at any minute. But with the toxin threat on London still active, they'll have to ignore this problem and continue with the mission.
Knowing that the United States are likely the ones to slash the flame arrestors, hoping to destroy the nuclear triggers along with the plane, Harry leaves headquarters to confront CIA liaison Bob Hogan (Matthew Marsh). "Think global, Harry," Hogan replies. "You've already lost one empire."
At headquarters, Ros discovers a lead in the toxin case in the form of a call to the Health and Safety Offices. An engineer has reported an exposed mains feed and refuses to work. The location? Molden House, a pumping station along the Thames. That has to be where the toxin is located. Jo and Malcolm (back from Heathrow) head out to investigate.
On board, Adam is surprised to learn that Ros is also on board, posing as a stewardess. She lets him know that Section D has an open line of communication directly to the phone at the back of the plane, providing that nobody else is using it to make PA announcements. As for the passengers, three of them have been flagged as threats.
Nicolas Faures (Paul Grunert): Advisor to the French nuclear program till he was carpeted for taking kickbacks.
Anastasya Poselskaya (Vera Filatova): Ex-FSB (Federal Security Service of the Russian Federation), no known employer, hiding 12 grand a month in cash.
Ebrahim Jannati (Kourosh Asad): Iranian passport, no available records.
Adam scopes them out in their respective seats, but he cannot make a move until Jo and Malcolm have completed their mission. He'll have to do his investigation quietly and without calling any attention. While Jo deals with the very pushy Faures, Adam manages to "accidentally" knock Poselskaya's luggage out of the overhead compartment and, in the ensuing confusion, manages to go through her things. He comes up with nothing. In the end, all three check out, so the courier must be somebody else. Ros takes the landing cards, flushes them away, and tells the other stewardess they'll have to start from scratch and make a new list.
This is the right course of action, as they notice that the person sitting in 19C (Demitri Goritsas) is not on the manifest. Adam goes up and tricks him into revealing his passport. He is Frank Lowell, he is an American, and he is likely their target. But they must still wait for the water supply threat to be contained.
While his employees try to solve the case a mile up in the air, Harry takes Ros' suggestion and visits Bakhshi at the Iranian embassy, hoping to reason with him. "Your government just authorized 70 billion pounds for a new trident missile system," he explains. "More than my country's entire foreign reserve. You call it defense. Why should we not, too?" However, Harry takes out his ace, hands Bakhshi a phone, and says that the presumed-dead Ana is on the other end of the line. Elated, Bakhshi takes the phone, exchanges sweet nothings with his wife, and his disposition turns. Saying he is not a terrorist, he informs Harry that the triggers are onboard the British flight. Alas, nothing he tells Harry is anything that Mi-5 doesn't already know.
At the Molden House pumping station, Jo and Malcolm enter and find what they're looking for. Unfortunately, after fiddling around with the gadget, an alarm goes off. It was a trap, a double-bluff designed specifically for them to trip. Racing to the control room, they yell at the technician to give them any information on how to shut down the plant. This station only balances the supply, though, and has no way of stopping anything. Asking where the main feed is, they race to the location deep underground with less than two minutes on the countdown, and with a swing of an axe, Jo is able to shut down the plant's power. As long as those pumps are dead, the water isn't going anywhere. The threat has been contained.
After hitting a few busy signals (damn those PA announcements!), Connie manages to get a hold of Ros and tells them to proceed with the mission. Adam immediately goes to Lowell and grabs his bag. "You've got the wrong guy," Lowell explains, but when the plane hits turbulence, he jumps up from his seat and engages with Adam in some intense hand-to-hand combat. Ros tries to intervene but Lowell tosses her off his back and into the aisle, just as Adam is able to get the upper hand, restrain him, and handcuff him to his seat.
But there's another problem. They are nearly to their destination, but the plane doesn't seem to be turning around. Adam calls into headquarters, where he learns that Harry has very much given the order to turn the plane around. Alas, the order has fallen on deaf ears. Adam bangs on the cockpit door and demands that they reroute, but is told in no uncertain terms that, should the crew suspect a terrorist hijacking, they will do no such thing. Adam takes Lowell's laptop and destroys it all, hoping that the triggers were inside.
With 90 seconds left before entering Iranian airspace, Malcolm phones in with an idea. Get everybody seated, so to the phone, turn on the Bluetooth, and text the numbers 757. While onboard the plane at Heathrow, he explains, "I set a charge to take out the fuel pumps. You said we might have to force a landing. It must have ruptured the fuselage. The pressure loss won't harm them if they get down fast enough." Ros texts the digits, and an explosion goes off. The plane loses altitude quickly, and while all the passengers manage to use their oxygen masks, thus allowing themselves to survive the sudden shift in pressure, Lowell cannot do so, and he dies within seconds.
As the plane lands safely at the Elazig Air Base in Turkey, Harry calls Hogan and learns a terrible truth: Lowell wasn't the target. He was a CIA agent Hogan put on the plane in case Adam couldn't complete the mission. They've just killed an ally. Wondering why the pilot refused to turn the plane around, even before Adam had started banging on the cockpit door, Harry realizes the awful truth: The pilot is the courier.
Harry calls Adam with the news, but when Adam tries to get to the cockpit, he is stopped and restrained by Turkish armed guards--it doesn't help that he's yelling and flailing about--and the pilot exits quietly, gets in a car, and leaves the airbase.
The nuclear triggers are out in the open, and Mi-5 is back to square one.
Hey! I Know That Actor!
Vera Filatova, who plays potential courier suspect Anastasya Poselskaya, is best known for playing the bisexual Elena, object of Jez's lust, on the sixth season of "Peep Show."