Captain John Carter, a weary Confederate soldier, is mysteriously transported to Barsoom (Mars), where the planet's lower gravity grants him superhuman strength. Captured by the warlike, four-armed Tharks, he earns their respect—and the enmity of their cruel king, Tal Hajus. When a Helium airship crashes, Carter meets Dejah Thoris, the fierce princess of the besieged city of Helium, and learns his lost friend James Powell has become Sab Than, the genocidal Prince of Zodanga, who seeks to control the ancient Atmosphere Plant that sustains all life on Mars. As Helium falls and Powell threatens to destroy the planet by tampering with the Plant, Carter must ally with Tars Tarkas, unite the warring Thark tribes, and confront his former brother-in-arms in a battle that will determine the fate of Barsoom—and whether Carter can ever find his way home.