Edgar Rice Burroughs, who is the nephew of the rebel widower veteran of the Civil War and gold hunter John Carter, has to attend the funeral of his uncle after his sudden death. He receives from John Carter's attorney his diary and weird instructions to be followed, and Edgar immediately starts reading the journal. In 1868, the Colonel Powell tries to force John Carter to join the army to fight against the Apache and arrests him. However, John Carter escapes and Powell chases him. They are attacked by the Apache and they hide in a cave. They are surprised by a Thern and John Carter kills him, and the alien's medallion transports John Carter to Mars. John has the ability to jump high and has his strength increased due to the gravity of Mars. However, he is captured by the Tharks and becomes their prisoner. He learns that Mars, called Barsoon, has been at war for thousands of years between the Helium and Zodanga, and this war is destructing the planet. The evil leader of Zodanga, Sab Than, has received a powerful weapon from the Thern Matai Shang. However, Sab Than proposes peace if he marries the Helium Princess Dejah Thoris. However, John Carter and Dejah Thoris fall in love with each other, and he decides to help the Helium people against the Zodanga people. But Matai Shang sends John Carter back to Earth and his last chance to return to Mars depends on his dear nephew's attitude.