What could go better with wieners than a flying space circus? Nothing! Which is why Humphree's all jazzed up at the chance to sell Galactic Hot Dogs as the official food of Crostini's Cosmic Carnival and Wonder Circus train. Cosmoe's not entirely convinced--but once his skills as a monster tamer are unveiled, the deal is done and the Neon Wiener is officially hooked onto the train. Only things aren't quite what they seem at this circus, and pretty soon Cosmoe realizes he and his buddies are in more danger than ever. To get to the bottom of it all, they have to travel somewhere pretty familiar, providing a glimpse at last into Cosmoe's past and how he ended up aboard the Wiener in the first place.