Harry Pearce finds himself in front of a tribunal over his willingness to trade the Albany file to save Ruth Evershed but he is temporarily reinstated at the request of the Home Secretary. Erin Watts had replaced him while he was on 8 weeks of enforced leave and he is pleased to hear she is to stay on as Section Chief. On his return he learns that a one-time agent, codename Sharecropper, had been trying to get in touch with him. Unfortunately, he was murdered just 72 hours before his return. Elena Gavrik, codename Tourmaline, is the wife of a Russian minister and was one of their best sources of information during the cold war. Harry thinks Sharecropper was trying to tell him that Gavrik is in danger of being exposed. For Harry however, Tourmaline is more than just another ex-agent. Written by garykmcd

Calum Reed is attacked outside Thames House and a laptop containing the information of A Grade MI5 Assets is stolen. A threat is made to release the details of the agents, one of which includes Martha Forde (Lydia Leonard) who has connections to Russian Minister Ilya Gavrik, meaning the Russian/UK partnership is also at risk. In a race against time, the team must recover the laptop before any of the assets identities are revealed. Meanwhile, Harry meets Elena at the Opera House to discuss who has been posing as him, as his relationship with Ruth becomes more frail. And Tariq finds a crucial piece of information about who stole the MI5 Laptop, but can he contact Harry and get back to Thames House in time? Written by SugarhorseAnna

Dimitri takes part in a Honey trap operation when known anarchist, Johnny Grier enters the country. Dimitri is tasked to honey trap Johnny's sister but the operation takes a turn with a twist of bluffs and lies as Johnny begins to suspect him which could end in tragedy. Meanwhile Elena reveals to Sasha why she betrayed her country and later meets Ruth to exchange information regarding Harry's impersonator. And Home Secretary William Towers has a job offer for Ruth but she is torn between her feelings for Harry. Written by SugarhorseAnna

Section D are facing a suicide bomb threat, when two prisoners are released. Having been trained for martyrdom in prison, one of the released convicts, Ashur Mohali is an MI5 asset, who's been made a promise that if he had spent two years in prison gathering information to help stop a terrorist attack, he and his daughter will be given UK citizenship. While the team try to prevent the attack and keep Ashur onside, Harry and Ruth make a decision to gather evidence against CIA Deputy Director Jim Coaver, now suspected of impersonating Harry and pursuing information from Elena Gavrik. Things takes a turn for the worst when Elena is attacked, and revelations lead Ruth to believe that it is indeed Coaver that is responsible for the attacks on the Gavrik's and MI5. Meanwhile, Erin has to make an impossible decision when the teams operation causes her to be compromised when her own daughter is put in danger. Ruth informs Harry of her offer from the Home Secretary, not wanting her involved in... Written by Sugarhorse Anna

Harry takes action against Jim Coaver and mounts an operation to bring him in and interrogate him over the attacks on the Gavrik's and MI5. Jim defends his actions explaining that his part in meeting with a CIA asset who then attacked Elena, was nothing to do with jeopardizing the partnership between the UK and Russia. Meanwhile Ruth is torn when the Home Secretary is informed that Coaver is missing, and is asked to give up his location. Coaver is taken by CIA operatives only to be tricked, when a team of mercenaries snatches him. Coaver, with his last words warns Harry to retrieve a laptop from the American Embassy as it will reveal who is behind the attacks. Harry then meets with Elena to discuss whether or not Ilya could be involved in the attacks and the two share an intense moment. Ruth again becomes torn when Harry enlists her help into getting Coaver's laptop out of the Embassy and back to him but Sasha Gavrik has other ideas. Harry is then pursued by the CIA, who plan to ... Written by AnnaSugarhorse

In the last ever episode, Harry is being extradited from the UK to be asked questions over CIA Deputy Director, Jim Coavers death. Elena Gavrik approaches Ruth at the signing of the Russian/UK partnership and reveals she has information but must only speak to Harry. The team are then forced to break Harry out of custody, taking Elena to a bunker to be interrogated. Elena then reveals the details of all the attacks on her husband and MI5, as well as truths about who was behind them shocking Harry and Ruth. She also insists there is an attack that very day, a threat with a bomb on a plane heading into London from Moscow. But is Elena to be trusted? As Erin, Dimitri and Calum race against time to find out who is behind the attack, Elena reveals some uncomfortable truths and lies to Harry. Ruth begins to question Elena's true motives and Harry takes drastic action when faced with a choice. Is the plane going to crash or does Elena want to force the UK to shoot it down starting conflict ... Written by SugarhorseAnna