Baixo Astral, an evil spirit who lives in the sewers, and whose mission is to bring unhappiness to the world, sees Xuxa on TV asking children to fight for a better world. Threatened by those words, he declares war on her and devises a plan: helped by his allies Titica and Morcegão, he kidnaps Xuxo, her dog. Helped by Xixa (a gypsy caterpillar) and Rafa, a rebel teenager, Xuxa goes on a mission to get her dog back and save the world from Baixo Astral.