After the Great Ecological Catastrophe, the ultrarich flee to Mars and leave the rest to perish. But among them a small child who developed immunity to the hostile planet remains. Decades pass and those on Mars venture back to Earth to do recon. When they spot a small human child, The Cub, they immediately try to capture it. This sets off a journey of escape, exploration and discovery through the urban ruins of humanity coupled with frantic cat and mouse chases.