Heather Salter uncovers a remarkable secret history of espionage and counterespionage, repression and resistance, corruption and courage, heartbreak and betrayal in Shanghai between the world wars. At the heart of this story lies the fate of Tatyana Moiseenko and Yakob Rudnik – known then only as Paul and Gertrud Ruegg – a couple arrested, tried, and imprisoned for running a clandestine communist spy ring. Against the backdrop of the battle between communism and anti-communism that would shape much of the twentieth century, this dramatic history provides a uniquely human perspective on the global volatility of the 1930s. Through Tatyana and Yakobs' eyes, Salter traces global police networks, MI6 in China, and the worldwide reach of the Comintern to shed light on the deep historical roots of antagonism between Russia, China, and the West.