After playing with her toy vehicles, Uma decides she wants to take a trip. She packs a small suitcase, and enlists Oobi and Kako to help make costumes of an airplane, a train and a boat. Uma rides these vehicles to the kitchen where Grampu has made a special snack for the kids. — NickJr.com (source)
Oobi, Uma, and Kako are playing with a set of toy vehicles. They imitate the sound of a train and invite the viewers to join them. This gives Uma the idea to go on a pretend trip to the kitchen. She wants to use her train, boat, and airplane toys to get there.
Oobi explains that the toys are too small and would not be able to transport her. Uma is disappointed, but Oobi tells her that they can create their own vehicles out of cardboard and paper. Uma jumps around excitedly and accidentally falls over. "Uma trip," she remarks. The boys laugh and begin to make a train from a box.
The next scene is an interview segment in which preschoolers talk about the trips they have taken. The scene cuts to Oobi, who has finished making a paper boat and a cardboard airplane. Uma is ready to take her trip. The characters sing the "Trip Wow" song. Oobi pretends to be a train conductor and takes Uma to the living room in their train.
Kako pretends to be a captain and brings her to the couch in the paper boat. Finally, Grampu dresses up as an airplane pilot and brings Uma to the kitchen. There, he has prepared a plate of brownies for the children. The group sings a reprise of "Trip Wow" as the episode ends.