Recruited into MI5 against a backdrop of the Cold War in 1972, Cambridge student Serena Frome, a compulsive reader, is assigned to infiltrate the literary circle of a promising young writer whose politics align with those of the government, a situation that is compromised when she falls in love with him.

In 1972, Cambridge student Serena Frome's intelligence and beauty land her a job with England's intelligence agency, MI5. Serena is tasked with infiltrating the literary circle of author Tom Healy. But soon matters of trust and identity subvert the operation.