In early 1941, with the Second World War going badly, Britain began an espionage operation in an attempt to persuade America to come to its aid. British Security Coordination, a spin-off from British intelligence run by a Canadian called William Stephenson, opened an office in New York and set about manipulating the news and spreading propaganda. The operation remained largely secret even after the war, with a few hints published in Stephenson's 1976 biography, A Man Called Intrepid. Coincidentally or otherwise, Restless begins that same year with Ruth Gilmartin finding out that her mother was a BSC agent.
Unknown to her and her late father, the woman they knew as Sally Gilmartin is in fact Eva Delectorskaya, half-Russian and recruited by the British secret service at her brother's funeral in Paris.
Eva cannot face telling her daughter the story and so has written it down, passing it to Ruth one chapter at a time. And that's how we get the story too, skipping between wartime Europe and America and 1970s Oxford in alternate chapters.
Now in fear of her life, for reasons we don't yet know, Eva/Sally needs Ruth's help to find Lucas Romer, the man who recruited her into the service and her former lover.
What follows is an excellent espionage thriller, though perhaps a slightly less successful novel. It's not obvious why the narrative division between wartime and the 1970s was necessary.
It helps because it emphasises the pervasiveness of espionage. The more Ruth reads of her mother's story, the more suspicious she becomes of those around her. Is the Iranian student to whom she is teaching English spying on his friends? Is Ludger, the German whose brother is her son's estranged father, involved with Baader Meinhof?
However, the potentially powerful relationship between Ruth and her mother isn't really explored. Other than calmly observing that everything she thought she knew about her mother was a lie, Ruth seems surprisingly unmoved. If Boyd is going to offer so little exploration of this relationship, why not set the entire novel during the war? It would have added to the suspense and claustrophobia of the narrative.
Still, it's a minor weakness in what is a very enjoyable read and a well-researched exploration of a period of recent British history that few people know about.