Earthlings are great pets here on planet Blorx. After begging her mom for years, Zira finally gets her own pet earthie, Rolo! His life in his new home is easy, with plenty of treats, naps, and walks to the earthling park — but also goopy canned food and a litter box. Rolo yearns for more. When the overzealous robots of the Animal Control Force chase him for an expired tag, he runs away and gets lost in the big city. He must outrun the earthling catchers and find his way home, but along the way, he seeks clues about the mysterious origins of earthlings. With the help of a stray street earthling, a wise museum curator, and an old blorxian star sailor, Rolo learns the legend of the mythical planet Earth. Meanwhile, Zira and her sulky teenage sister Riffa must find her poor lost pet before the earthling catchers take him away. But Rolo may have ambitions of his own.

This fast-paced adventure is cleverly comical, thought-provoking, and genuinely heartfelt. Together, Rolo, Zira, and Riffa face the challenges of growing up and growing apart in this upside-down world.