In 1942, in a quiet village in the leafy English Cotswolds, a thin, elegant woman lived in a small cottage with her three children and her husband, who worked as a machinist nearby. Ursula Burton was friendly but reserved, and spoke English with a slight foreign accent. By all accounts, she seemed to be living a simple, unassuming life. Her neighbors in the village knew little about her.

They didn’t know that she was a high-ranking Soviet intelligence officer. They didn’t know that her husband was also a spy, or that she was running powerful agents across Europe. Behind the facade of her picturesque life, Burton was a dedicated Communist, a Soviet colonel, and a veteran agent, gathering the scientific secrets that would enable the Soviet Union to build the bomb.

This true-life spy story is about the woman code-named “Sonya.” Over the course of her career, she was hunted by the Chinese, the Japanese, the Nazis, MI5, MI6, and the FBI—and she evaded them all. Her story reflects the great ideological clash of the twentieth century—between Communism, Fascism, and Western democracy—and casts new light on the spy battles and shifting allegiances of our own times.