An international prize of one billion has been offered to the first man to complete an interplanetary trip, and Dale Curtance, a millionaire adventurer, emerges as the British entrant. With a hand-picked crew, he blasted off from Salisbury Plain in the spaceship Gloria Mundi, destination—the planet Mars. Once free of Earth's atmosphere, they discover a stowaway—a woman. Her extraordinary story helps them prepare for the dangers they encounter on the Red Planet, and the fantastic world that exists there.