April 12, 1945: After years of conflict in Europe and the Pacific, America is stunned by news of President Franklin D. Roosevelt's death. In an instant, Vice President Harry Truman, who knows nothing of the top-secret Manhattan Project to develop the world's first atomic bomb, must confront one of the most consequential decisions in history. Here veteran journalist Chris Wallace tells the gripping true story of this turbulent time, offering portraits of Albert Einstein, Robert Oppenheimer, and Truman, but also "Calutron Girls" like Ruth Sisson in Oak Ridge, Tennessee, and ten-year-old Hiroshima resident Hideko Tamura, who survived the blast at ground zero.