Sidney has to go and collect Percy's new wheels, but his memory is not very good. Thomas suggests that Sidney to make up a song to help him remember.

Percy still remembers the time he raced against Harold the Helicopter. One day, he is bringing letters to Santa, and thinks that Harold is calling him slow and out of date again, and decides to not listen while he tries to make up for lost time due to the snow.

Philip thinks that Toby is a boxcab just like himself and wants to become friends, but Toby is not so keen on doing the same thing as Philip and finds him rather persistent and overwhelming, by having a race to the Ffarquhar Quarry.

When Henry is given the job of pulling the express, Gordon goes on strike. Passengers start saying that Henry takes the express even more gently than Gordon does.

Devious Diesel is known to be mean against the other engines on Sodor, and that is how his diesel friends like it. One day, Thomas spots Diesel being friendly with some ducklings, and threatens to tell everyone whether he is mean or not.

Thomas has trouble with the Troublesome Trucks yet again in the yard. When Samson arrives with a goods train, his brake van, named Bradford, sees Thomas and offers to help.

Samson comes to Sodor to help out with bringing stone from the Blue Mountain Quarry.

Despite being different from each other, Ryan and Daisy work together on the branch line between Harwick and Arlesburgh.

Daisy does not think she would ever need Annie and Clarabel when she is tasked to take care of passengers on Thomas' Branch Line while he is put on quarry work. But one day, she does need them due to her popularity among Thomas' passengers.

Snow has arrived early to the Island of Sodor, and Donald and Douglas work together to clear the tracks. While at a junction, they have a choice: to clear Thomas' branch line or clear the track to the Search & Rescue Centre.

James is a mixed traffic engine on the Island of Sodor. He likes pulling coaches more than trucks. A few times, he shows off too much, and wants to be the centre of attention.

A heavy storm is arriving at the Island of Sodor. At Arlesburgh, Skiff's new captain, Joe, checks that everything is secure. Duck and Oliver are just finishing their passenger runs, and tease Skiff for being a little rail boat.

Sir Topham Hatt gives Daisy a special, to bring some entertainers for a performance. Daisy is excited, and boasts that the entertainers would choose a railcar like her.

Thomas enjoys the competition of Max and Monty but begins to question his friendship as Max and Monty mess about while working, affecting Thomas' work.

Connor boasts of being the fastest engine, but one day, he breaks down on the Island of Sodor and goes to the Steam Works to be repaired. Connor starts to worry it will happen again if he goes too fast and after that, Connor becomes the slowest engine on the island.

James is asked to take the Mayor of Sodor and Sir Topham Hatt to a party at Callan Castle, but has to do other jobs first and every job he does, he gets dirtier and dirtier.

One sunny day, the tracks buckle and bend and Dowager Hatt gives the Fat Controller a new hat, which everyone calls a safari hat. The Fat Controller gets sick of everyone teasing him and tries to find a way to get rid of it.

Some visitors come to the island to take photos of engines. They visit the Arlesdale Railway and take pictures of the small engines, but Bert is cross that they will not take pictures of him.

Duck's driver boils an egg in his whistle, which is now clogged and makes a funny noise. The engines tease Duck about his whistle, especially Mike who says engines without whistles are improper engines.

Mike is annoyed of always being stuck behind animals, Rex boasts to the small engines about how easy wool deliveries are.

Henry is accidentally given some "Glow in the Dark" paint at the Steam Works and is confused as to why everyone he comes across runs away from him. It is shown that his paint is glowing and laughs at the misunderstanding.

One night, Percy is frightened by a strange sound from under the bridge at the Watermill. Toby is worried, though Thomas does not believe it to be true, until he too hears the sound.

When a rail Zeppelin called Hugo comes to Sodor, everyone at first is very impressed. However, Stephen is concerned they will be replaced by engines like Hugo, making the engines worry about their future. They take their anxiety out on Hugo, making him feel unwelcome.

After word of an airship resembling Hugo spreads, Hugo feels he should be able to fly just like it. He gets some encouragement from Skiff and tries to take off into the sky like an airship on Gordon's Hill, like his non-rail aerial counterpart.

Judy and Jerome are upset that they are never taken out any more as Rocky is now the official crane of the island. Ryan, who feels sorry for them, takes Judy and Jerome out for a change of scenery.

Skiff hears word of a mermaid statue arriving at a museum at Arlesburgh Harbour, believing it is real.