During the day, Duncan complains to Rheneas about the cold weather. He then complains to Rusty about the apparent lack of sand. Later, he complains about the extra passengers slowing him down to Skarloey causing the engine to start losing his Christmas spirit.
By the time Skarloey returns to depot, he does not feel very festive at all. Neither do Rusty and Rheneas. Thomas arrives and tells them that even Duncan will be impressed by the brightly lit depot. Sure enough, Duncan arrives and starts complaining. Thomas tells his narrow gauge friends that the Fat Controller is giving all of the standard gauge engines a new coat of paint. Duncan thinks this is unfair, but Rusty informs him that Mr. Percival is planning a similar treat for his narrow gauge engines. Duncan is pleased, but goes off moaning as usual. This gives Rusty an idea.
The next day, Duncan travels to the Steamworks for his fresh coat of paint where he finds the Thin Controller talking to Victor. Mr. Percival tells Duncan that he is upsetting the other engines with his constant complaining and that he will only get his coat of paint if he is cheerful for the rest of the day. Duncan accepts the challenge and sets off to work.
On his way, Duncan meets Rheneas at a junction. Rheneas reminds Duncan to go slow on the icy rails. Duncan thanks Rheneas for the reminder. At Crovan's Gate, Duncan has to wait while all the passengers climb aboard his carriages with their extra luggage. Skarloey arrives and notices that Duncan's attitude has completely changed since yesterday. Shortly, Duncan gets held up at a frozen level crossing. To pass the time, the passengers start to hum a Christmas tune. Duncan doesn't like the humming at all, but he grins and bears it.
Later, Duncan gets stuck behind Luke on a slippery hill. Try as he might, Luke cannot reach the summit; his wheels will not grip the rails. Duncan is very impatient with Luke and upsets him. Unfortunately, Rusty is watching Duncan with interest. Duncan realises that he has upset Luke and decides to help his friend. As Luke's sandbox is empty, Duncan drops some sand on the line himself. He then buffers up to Luke and gives him a push to the top of the hill. Rusty has seen everything. Duncan feels sad; he knows that he lost his temper and that means no new coat of paint for him.
The next morning, Duncan heads to the Steamworks anyway to apologise for his behaviour. As Duncan begins to explain to Mr. Percival he is cut off mid-sentence. Mr. Percival explains that Duncan had done a very kind thing in helping Luke and such usefulness should be rewarded with a new coat of paint. Mr. Percival also says that he had been wrong to make Duncan be cheerful all day. Rusty goes on to say that he is just that sort of engine and, as Luke points out, it doesn't make him any less useful.
Tropes featured in the episode:
- Appeal to Inherent Nature: After being called out for his complaining and making the other engines upset by Mr. Percival, Duncan explains that it's the way he is and he can like it or not. Mr. Percival objected to that.
- Break the Cutie: Skarloey suffers this the most out of Duncan's complaining; after Duncan complains about the passengers slowing him down, Skarloey loses his holiday spirit and is crestfallen once he meets up with Rheneas and Rusty.
- Christmas Episode: Just like every single Christmas Episode in this series.
- Cold Turkeys Are Everywhere: In order to receive a new coat of paint, Duncan must avoid complaining. It doesn't work, but Mr. Percival rewards him anyways since he helped Luke.
- The Grinch: Duncan.
- Jerkass Realization: Duncan undergoes one after complaining to Luke struggling up the hill because of his empty sandbox.
- Jerk with a Heart of Gold: Duncan in the end.
- Rule of Three:
- Duncan tells Rheneas that it's too cold, Rusty that there's not enough sand for their sandboxes, and Skarloey that the passengers keep slowing him down.
- Duncan manages to hold it in at the station and level crossing, but when he gets to Luke he loses his temper.
- Scenery Porn: The scene where Duncan crosses the bridge is gorgeous.
- Shout-Out: Duncan keeps saying "Bah, humbug" throughout the episode.
