The adventure of a lifetime occurs not in the outer reaches of space, but inside the human body. An elite team of medical and scientific specialists race to save a top government scientist who is suffering from a blood clot on the brain. Their mission: be reduced along with their submarine-like craft to microscopic size, enter the bloodstream of the ailing scientist, and journey to the brain to perform an emergency procedure. With only sixty minutes to complete their mission, the scientist find themselves fighting off an attack by white corpuscles, caught in a tornado-like storm in the lungs, and struggling to survive sabotage from one of their own.