London, England, on the eve of World War II. Guinevere Pettigrew, a strict governess who is unable to keep a job, is fired again. Lost in the hostile city, a series of fortunate circumstances lead her to meet Delysia LaFosse, a glamorous and dazzling American jazz singer whose life is a chaos ruled by indecision, a continuous battle between love and fame.

During a handover to the head of counter-terrorism of MI5, Harry Pearce, a terrorist escapes custody. When Harry disappears soon after, his protégé is tasked with finding out what happened as an impending attack on London looms, and eventually uncovers a deadly conspiracy.

Former British soldier Jonathan Pine navigates the shadowy recesses of Whitehall and Washington where an unholy alliance operates between the intelligence community and the secret arms trade. To infiltrate the inner circle of lethal arms dealer Richard Onslow Roper, Pine must himself become a criminal.

It’s a new world for the Spooks team: Ros’s death and a new coalition parliament herald in an era of re-assessment of the role of Britain, MI5 and even the life of a Spook. Faced with Ros’s barely attended funeral, the team come to question what a person sacrifices when they become a spy, provoking Harry to make an unexpected offer to another member of the Team.

Further challenges await Harry in the form of the new Government and colourful new Home Secretary, William Towers. Working for a government doing whatever it takes to stop the country from sinking into historic economic disaster in their first year in office, Harry’s instincts are challenged as he is forced to bend to the will of those more powerful.

There are some new faces on the Grid. Beth Bailey — an ex-mercenary who wants to hang up her boots in Iraq and find a more meaningful existence, defending the realm. Desperate to impress, she leaves some vital details about her past off her application form. Then there’s Dimitri Levendis: ex-SBS (Special Boat Service) who proves how capable and heroic he is in an impossible situation.

The eighth action-packed series finds the team in a race against time to rescue Harry, who has been kidnapped by rogue Russian agents. But as they dig deeper into his disappearance, they find a trail that leads to Iraq, and a conspiracy that involves the CIA, MI6 and some missing weapons-grade uranium. Could Harry know where it is? And how is former team member Ruth Evershed, recently returned to the security of MI5 having fled her new life in Cyprus, connected to it all?

Defending their country, deceiving their friends — it's all in a day's work for the agents at MI5, the Security Service. The elite team tackle organised crime, espionage and terrorist activities, as well as the conflicts and power struggles back in the office. There's a car bomb in Liverpool, a siege in the Turkish embassy and the murder of a double agent, not to mention the difficulty of having to lie to loved ones about who you are and what you do.