Dunbar is training the trainees to use the new Painting wagons, and Wilson can't paint properly, and accidentally paints a moustache on Dunbar! Old Puffer Pete takes him to Old Chuggington to practise. Wilson tries to find the others, but can't, so paints his shed door instead, painting a butterfly that landed on the roof. Chatsworth comes by, and says that he can't paint it. However, Chatsworth finds him something to paint - Dunbar, Koko, Wilson and Brewster on the depot wall!