NASA responds to John F. Kennedy's challenge of landing a man on the moon with a group of new astronauts for the Gemini Program, who work toward the eventual lunar voyage with a series of risky and groundbreaking earth-orbit missions.

The glare of the public eye, conflicts among the crew, disastrous simulations, and a series of harrowing last-minute crises threaten the Apollo 11 astronauts' success at pulling off NASA's crowning achievement—the first lunar landing.