While RedCat and WhizzKitty are in the tree house playing with their racetrack, they receive a message. It comes from the six national champions of the European Kart Competition. They challenge everyone to a competition. Whoever wins all races gets the Golden Euroster, which no one has ever managed to do before. Of course they want to participate. However: Brutus and Max discover this and decide to join in, so that they can buy a lot of cheese and bones with the star. The four of them travel to Europe to take part in the race and compete for the star.