Toad and Spud's amazing adventure is the fourteenth episode of the fourth season of Yuna's Princess Adventure.
After dropping off supplies for the carnival at Wallace and Gromit's school, Oliver heads for the Steamworks to have a inspection, leaving Toad in the yards. A little later, Spud the scarecrow comes up and decides to hang with Toad since he has nothing else to do. But soon it stats to get boring from the prospect of sitting around for ages doing nothing, then Brewster and Zephie pull in the yards searching for a brakevan for Brewster's train. Toad offers to go, but he doesn't have anyone to operate his brake. But Spud volunteers to be Toad's brakeman and calls himself "Spud the Brakeman Scarecrow". After Brewster and Zephie pick up the frieght train and Zephie shunts Toad on the back, they set off. Toad is enjoying his time with the 2 Chuggington engines. But as they go up a big hill, Brewster hits some stones on the line which causes the train to uncouple itself. Soon enough Toad starts rolling back down the hill with the cars, Spud then starts to panic and yells out. Zephie and Brewster quickly turn around and give chase. At first, Toad and Spud enjoy the ride, but their enjoyment soon ends, as the train crashes through a crossing that was closed.Brewster and Zephie try their best to catch up to the train but it's moving quicker than they are. Then train then races through Canterlot station, at this point Toad realizes that they're heading straight for Wallace and Gromit's school! Spud then manages to calm himself down and he throws Toad's brakes on but they are still going too fast. Spud then gets an idea, the scarecrow starts climbling along the train and starts throwing the brakes on each car. At this point, the reach the school gates and crash through the gates. Spud then starts blowing a whistle he found to warn everyone at the school that they are racing towards them. Everyone at the carnival hears the whistle and sees Toad and the the runaway cars speeding straight towards them. They take cover and prepare for the crash. Toad knows it's up to him to save them all now. With sparks flying from his wheels, and Spud cranking on a boxcar's brake as hard as he can they sam into the buffers but don't crash through. But the force of impact sends Spud and a crate flying, Spud hits the ground landing in front of a stand, while the crate catapults an apple pie, a dish of ice cream, and a huge chocoate and black cherry cake. Cheese Sandwich manages to catch the pie and the ice cream but the cake lands on Spud. Brewster and Zephie pull in a little later, just as the Dean Hardscabble demands to know what has happened. Brewster and Zephie are about to take the blame, but Toad covers for them by saying that they just hit some stones and it was all an accident. Later that day, after Brewster and Zephie made the delivery, Oliver came back.
- Music score - Finale (from The Lone Ranger)