Ruth Evershed is a fictional Senior Intelligence Analyst seconded from GCHQ to MI5, featured in the British television series Spooks, also known as MI-5 in the United States. Ruth was played by Nicola Walker from the time the character joined the show in 2003, until Walker left to have a baby in 2006. She returned in 2009 and continued her role until her character's death in the final episode of series 10.
Background
Ruth was a graduate of Corpus Christi College, Oxford, where she studied classics. After obtaining her degree she applied for a job in GCHQ. It is established that she was fluent in multiple languages including Greek, French, Latin, Russian, Arabic, Mandarin Chinese and Wu Chinese. She proclaimed that her Cantonese is "horrible".
Initial tenure
Ruth was introduced in Series 2 as an intelligence analyst, seconded from GCHQ. Although initially asked to spy for GCHQ, her supreme intelligence amongst other qualities quickly made her an established and trusted member of the team. She formed strong bonds with Tom Quinn, Zoe Reynolds, Danny Hunter and in particular Harry Pearce.
During her time in MI5, a romance starts to develop between Ruth and Harry. Although at first they refuse to act on their feelings, refraining from ever mentioning that something more existed between them, Harry is eventually goaded to act when he is called on his relationship with Ruth by Juliet Shaw after a failed coup d'état from within the British intelligence community at the start of Series 5. In the next episode, he finally asked her to dinner, which she accepts. The date goes well and they bond over their desire to travel for something other than their work, and Ruth is intrigued by Harry's implicit offer that she could travel with him on such a tour. But Ruth, ashamed when people start rumours about their relationship, calls it off at the end of the episode.
Temporary departure
Ruth's final episode was series 5 episode 5, "The Message". She witnesses the suicide of Mik Maudsley, Head of Security at Cotterdam Prison, which was under investigation after a fire which occurred there, killing seven terror suspects. She is suspected of Maudsley's murder. Evidence proving this was faked by Oliver Mace, in order to persuade Harry to join a group that supports torture. Although Harry is willing to go to prison to save her, instead she fakes her own death so that he can continue to fight for MI5. Meeting for their final goodbye, Harry tries to declare his love for Ruth but she tells him to leave it as "something wonderful, that was never said." She and Harry share a goodbye kiss as she leaves on a barge to venture into the unknown.
Return
Ruth returns in series 8 episode 1, after she and her household are attacked. Ruth had settled down in Polis, Cyprus with a Cypriot doctor and his son. She is told that Harry has been abducted. Lucas and Ros realise that Harry and Ruth share knowledge that the abductors want. During the ensuing case, the doctor is shot dead. Ruth is willing to give up the knowledge to save the boy but Harry refuses, leading to a falling out between them even though the boy survives. Since Ruth and the doctor were never married, she does not have legal guardianship and the boy returns to Cyprus to live with his aunt. Harry tells Ruth he will "sort things out" for her since she is back in the UK, despite being legally dead. He also says she can come back to Section D if she needs work.
Ruth returns to the grid full-time in episode 3, quickly slotting back into her old role while remaining ambivalent about the cost of involvement. At the end of that episode she is left distraught after friend and colleague Jo is killed in a hostage situation. With Harry's support, she moves on and works alongside the team in its operations against the growing threat of Nightingale.
After Ros's death, Harry asks Ruth to marry him. Ruth declines, but later reveals her refusal isn't because she doesn't love him, but that, after all they had gone through together they had already become soul-mates, and didn't need to demonstrate it in such a way. Ruth also convinces Harry to reconsider his resignation. In the final episode of series 9 she is captured, handcuffed and gagged by Lucas North as he causes a distraction that enables him to get her into his truck, as a hostage for Harry to deliver to Albany. He secures her to a chair and gags her again, but after giving his demands he ungags her, and when she asks to speak to Lucas he says he is not there. She nearly dies from an anaesthetic drip, though Maya, Lucas's girlfriend, convinces him to tell the team where her location is after he gets the file.