When Spurs Jackson, Hank Roper, and Strong Bow return to Mars in a rocketship, they are greeted by Queen Thula, who instructs them to not remove their helmets. The atmosphere of Mars has been diminishing, and it is too thin for them to breath. Through investigation, Spurs Jackson and his Space Vigilantes discover that someone is suctioning off the atmosphere, condensing it into liquid, and storing it.