When Kate runs out of train tracks, her surprise special delivery for Mom goes off the rails - until she and Mim-Mim take a ride on the Mimiloo Express and learn how to improvise.

Kate and Mim-Mim help their friends track down some giant dinosaurs who have run off with Tack's invention, the Larger Barger.

When Lily gets swept up into the clouds by a giant, fast-growing beanstalk, Kate rallies the gang to climb up after her, with Boomer leading the way.