Elise

Elise opens with an attempt on Hilda Pierce's life. Before the title sequence, she is shot on the steps of MI5 by a young man who says, This is for Elise, and flees. She survives and is taken to hospital, and the attack draws Christopher Foyle into the wartime past of the woman who recruited him.

Pierce had run agents for the Special Operations Executive, and it is the French section that matters here. Her former SOE colleague Sir Ian Woodhead, now the director of MI6, visits her. Foyle searches Pierce's flat for diaries and photographs and follows the trail to the Special Forces Club, an ex-SOE haunt, where a former colleague, James Stafford, gives him a name: Sophie Corrigan, whose operational code-name was Elise. Her mother, Joyce Corrigan, tells Foyle that Sophie was killed on her first mission, behind enemy lines in France in May 1944, and that her son, Miles, blames Pierce for sending her to her death. Miles is the man who shot Pierce, a young man with a grievance rather than a plan, and he tells Foyle he intends to kill everyone he holds responsible.

Foyle links the shooting to a larger question: whether someone inside SOE betrayed the French section. Nine agents under Pierce died in France, and Pierce believes the losses were the work of a traitor code-named Plato. Elizabeth Addis, whose presence as Pierce's colleague was settled in the previous episode, had compiled a shortlist of suspects, and Foyle works it: Eric Caplin, a civil servant in the pay of the racketeer Damian White; Peter Hawtrey, who has gone missing; and Luc Tellier, now a civilian pilot. When Miles Corrigan takes a shot at Caplin and is killed in the attempt, his last word is a further name, and the threads close.

The truth is that there was no Plato. The information that killed Sophie Corrigan and the others did not come from a mole; it came from Woodhead, who knew the French network had been compromised and allowed the agents to be dispatched anyway. The betrayal was not a spy's work but an officer's decision, taken knowingly, that the missions should go ahead. Foyle carries the finding back to Pierce, who realises that her hunt for a phantom traitor had been misdirected and that her old colleague is responsible for the deaths of the men and women she sent out. She confronts Woodhead in his office and kills him and herself with a hand-grenade, the programme's last act of violence.

A second thread runs beside it. The racketeer Damian White has made his money from illegal clubs, the black market and, latterly, from selling state secrets to the Russians, his association with the Soviet agent Arkady Kuznetsov the link between organised crime and espionage. White's men steal a lorry load of cigarettes and kill the driver, and when Adam Wainwright presses the police to act against the black market he is set up: stolen cigarettes are planted in the Wainwrights' home and he is arrested. Sam examines the file on White, discovers that he is paying off a senior police officer, Chief Superintendent Alan Usborne of West Peckham, follows the two men and photographs them with Glenvil Harris as her witness. White is arrested for treason and Usborne for receiving stolen goods, and Adam is cleared.

The strength is the disclosure that there was no mole. The episode turns the spy hunt inside out by making the deaths in France the product of an ordinary, institutionally approved decision rather than a traitor's treachery, and it gives Pierce a resolution that is at once an atonement and an indictment. Its weakness is convenience: both the Killing Times and a long-running episode blog note that the pieces fall into place too easily for a finale, with suspects uncovered late, and one review found that Kitchen, the programme's centre, was given too little to do.

Elise ends the programme. It closes the MI5 thread opened in series 7, kills its central intelligence figure, and gives Foyle and Sam a private ending: at Pierce's funeral Foyle turns away from Elizabeth Addis, declining a future with a woman who can live with the truth that destroyed Pierce, and Sam at last tells him she is expecting a child, pregnant without permission, as the two of them joke, and asks him to be the baby's godfather. The audience figures survive unresolved: the per-series table gives 5.55 million viewers while the Digital Spy overnight report of 19 January 2015 gives 3.54 million at 9pm plus 490,000 on the +1 channel, and neither is preferred. The final shot closes on the dead rather than the living.