The diesels

One summer day, Thomas is happily puffing along the tracks, until he spots smoke in the sky ahead. He finds Percy already helping to fight a fire at a farmhouse, with the Fat Controller overseeing the effort to extinguish the blaze. He starts to help fight the fire until Belle, the new fire locomotive, arrives to save the day. After the fire is put out, Belle runs out of water and Thomas and Percy shunt her to the Steamworks. Once there, Belle is congratulated by the Fat Controller for her brave work, but he says that another fire engine is needed on the Island of Sodor. Belle recommends Flynn, so it is arranged to bring him over from the Mainland.

When Thomas starts to spend all his time with Belle, Percy feels left out, and for some reason, Diesel is being nicer to him than normal. Percy is supposed to deliver Flynn's hose to the Rescue Centre, but Diesel convinces him to go to the VicarstownDieselworks. When Percy reaches the fork, despite Thomas earlier telling him how diesels can be devious, he takes the track to the Dieselworks. At the Dieselworks, Percy is made to feel very special by none other than Diesel 10. Percy wants to leave so that he can deliver Flynn's hose, but Diesel 10 says that Dart can take it instead. Percy learns all about the state of the Dieselworks. The diesels say that they had told the Fat Controller that the Dieselworks needed repairing, but he only listens to steam engines. Percy says that he will ask Thomas to tell the Fat Controller because he always listens to Thomas.Meanwhile, Flynn arrives at the docks and sets off for the Steamworks. When Percy finds Thomas at the Steamworks, everyone is admiring Flynn. Percy tries to tell Thomas about the Dieselworks, but Thomas interrupts saying that the Fat Controller had asked him to show Flynn around the Island and he rolls over to the new fire engine. Percy very sadly rolls away to Tidmouth Sheds.

The next day, Percy returns to the Dieselworks etc.