In 1946, codebreaker Meredith Gardner discovered that the KGB was running an extensive network of strategically placed spies inside the United States, whose goal was to infiltrate American intelligence and steal the nations military and atomic secrets. Over the course of the next decade, he and FBI supervisor Bob Lamphere worked together on Venona, a top-secret mission to uncover the Soviet agents and protect the atomic bomb. Opposites in nearly every way, Lamphere and Gardner relentlessly followed a trail of clues that helped them identify and take down the Soviet agents one by one, including Julius and Ethel Rosenberg. At the center of this spy ring, seemingly beyond the American agents grasp, was the mysterious master spy who pulled the strings of the KGBs extensive campaign, dubbed Operation Enormoz by Russian Intelligence headquarters. Lamphere and Gardner began to suspect that a mole buried deep in the American intelligence community was feeding Moscow Center information on Venona. They raced to unmask the traitor. This twisting thriller begins at the end of World War II and leads all the way to the execution of the Rosenbergsa result that haunted both Gardner and Lamphere to the end of their lives.