Bulgy's wish for the passengers to use the roads instead of the railway comes true when he accidentally contaminates the water in a railway water-tower.
The engines worry about Rebecca's first encounter with the Troublesome Trucks, recalling many of their own mishaps, but Rebecca proves she can handle them in her own way.
When Rajiv loses his crown, he refuses to do any work. That evening, Rajiv learns that he can be a really useful engine with or without his regal ornament.
When Diesel gets cross, he decides to get the other diesels into trouble by sending Rebecca to do their jobs, badly, but Diesel's trick is found out at the end.
The steam engines must work overtime to unload cargo from the docks when a series of accidents puts Porter and all of the diesel engines out of action.
When Thomas fails to turn up for a routine stop on a snowy day, Percy panics that he has had an accident and causes unnecessary confusion and delay by insisting on a search.
Thomas discovers that he doesn't know as much as he thinks he does while working in Italy. He also learns the intriguing tale of the legendary Lost Engine and runs into trouble on an old, abandoned line.
When Jack and the Sodor Construction crew arrive in Italy, Thomas is jealous of their amazing discoveries. Then, an accident leads Thomas to making the biggest discovery of all.
