The wise Sir Handel, brash Duncan and powerful Mighty Mac travel the railway high in the hills.
When a storm comes to the hills of Sodor, the little narrow gauge engines are called to help bring the sheep to safety. Skarloey is frightened of the lightning and while Rheneas and Peter Sam puff up and down with the sheep, Skarloey hides. The other engines soon run out of coal, forcing Skarloey to help out. With sheep still in danger, Skarloey puffs into action. Thinking only about the sheep, he realizes that he can do more than he thought! When Duncan becomes a little fed up with his straw deliveries, he decides to find a more important job. He abandons his straw collection to try some other engines' jobs instead. He collects Rusty's sightseers, but is soon distracted by pulling Skarloey's cows to the market - he does neither of his new jobs properly! This makes a lot of people upset - and Rusty and Skarloey get the blame! Duncan tells the truth and puts everything right. He goes back to delivering straw - it's a very important job after all.