In 1958, with the Cold War pushing the United States and Soviet Union into open competition over space, NASA launches Project Mercury as the country's first human spaceflight program. The film traces the effort from its origins in the wake of Sputnik through the selection of the Mercury Seven astronauts, the engineering behind the capsule, and the unmanned test flights that preceded crewed missions. Archival footage covers the launch pads at Cape Canaveral, mission control rooms, and the suborbital flights of Alan Shepard and Virgil Grissom before John Glenn's orbital flight aboard Friendship 7 in 1962. The program's stakes are laid out plainly: after the Soviets put Yuri Gagarin into orbit first, Mercury became the proving ground for whether the United States could catch up in a race being watched by the entire world. The documentary follows the technical setbacks, the political pressure from Washington, and the six missions that took American astronauts into space for the first time.