It's the 10th and final series of award-winning, enduringly popular spy drama Spooks, with the Grid in turmoil following the drama of series nine, not least the betrayal of Lucas North (Richard Armitage). Erin Watts (lara Pulver) is the acting head of Section D following the suspension of head Harry Pearce. But Harry survives his MI5 employment tribunal and is quickly back in the heart of the action. Buried secrets are unearthed when Max Witt, a retired spy and Harry's colleague in Berlin during the Cold War, is found murdered by an unknown assassin. Meanwhile Ilya Gavrik, Russia's foreign ambassador and Harry's opposite number in the KGB for much of the Eighties, has flown into London to negotiate a ground-breaking strategic partnership between Russia and the UK. Harry makes clear his feelings about the partnership, but the Home Secretary insists he put a lifetime of animosity behind him and make friends with the old enemy; a request made even more urgent when the killer of Max Witt now appears to be targeting Gavrik. Gavrik is in the UK with his wife, Elena, and they are joined by their son, Sasha, a London-based FSB officer tasked with the security of his family. Elena was Harry's secret asset in Berlin during the Cold War when he got her to spy on her husband. But when Elena reveals he's asked her to spy for him again, Harry realises that someone is pretending to be him. Who is it and, more importantly, why?