When Caro and Marce go on vacation they find a new friend, Buji, and just like Dibu, she is a cartoon animated kid. Abu, Pepe, Víctor, Leo and Dibu are left alone at home and they have quite an adventure when they decide to sign-up Dibu in a go-cart race.

Facing an imminent attack from Mars, planet Earth sends Dibu to Mars as a peace ambassador -- the only hope for averting the attack. Amazingly, he finds a friendly population, whose only issue is that they are fed up of their planet being used as a nuclear dump site. Besides averting the Martian attack, Dibu also inadvertently manages the save hit planet from the diabolical designs of an ambitious general