In 1946, genius linguist and codebreaker Meredith Gardner discovered that the KGB was running an extensive network of strategically placed spies inside the United States. Over the course of the next decade, he and young FBI supervisor Bob Lampshere worked together on Venona, a top-secret mission to uncover the Soviet agents and protect the Holy Grail of Cold War espionage - the atomic bomb. But at the centre of this spy ring was the mysterious master spy who pulled the strings of the KGB’s extensive campaign. Lampshere and Gardner began to suspect that a mole buried deep in the American intelligence community was feeding Moscow Centre information on Venona... A breathtaking chapter of history and a page-turning mystery, this twisting thriller begins at the end of World War II and leads all the way to the execution of the Rosenbergs.