The adventures of Thomas the Tank Engine and his friends on the island of Sodor. Thomas is often in trouble and finds it difficult to be a useful engine.
The Fat Controller asks Sidney to collect Percy's new wheels but Sidney worries he might forget as his memory isn't very good. Thomas suggests making up a song for Sidney to remember.
CGI animation. When Gordon is late, Henry is asked to pull the Express. Gordon is not happy that he has to take over Henry's work and goes on strike.
When Thomas finds Diesel lovingly fussing over some baby ducklings, Diesel promises to be nice to everyone in exchange for Thomas's silence.
Bradford the Brake Van arrives in Sodor and is a stickler for the rules. Thomas decides to go off without him and gets into trouble.
CGI animation. Samson and Thomas are taking stone from the quarry to the docks, but Samson takes too many trucks and gets into difficulty, making the pair of them late.
Daisy gets a good-natured new goods engine named Ryan to help her out with some of her passenger duties.
CGI animation. James likes to show off and be the centre of attention, but one day he shows off so much that the Fat Controller takes his coaches away!
CGI animation. During a storm, Skiff the tiny railboat gets blown down the track and right into a tree that lightning has been brought down across the branch line.
CGI animation. Daisy decides that her new passengers are too special for her to pick up children with ice lollies or pull a dusty baggage truck.
CGI animation. When Percy runs into a snowdrift delivering the Christmas mail, Harold volunteers to take the letters for him. Then Harold runs into trouble too.
CGI animation. Sodor is covered in heavy snow! Donald and Douglas must push the snowploughs, but they fall out about which line to clear first.
Thomas is sent to work in the quarry, so Daisy is asked to take on his usual responsibilities. Annie and Clarabel get taunted by Daisy because she thinks she doesn't need them.
Thomas is irritated by dumper trucks Max and Monty's careless antics.
Connor breaks a coupling rod and, after repairs, goes from the fastest engine on Sodor to the slowest with his newfound caution.
James asks to be the one to take the Fat Controller and the Mayor of Sodor to a ball, but worries when he gets a scratch on his paintwork right before the job.
A very hot day on Sodor causes the tracks on Thomas' branch line to buckle and a change of hat for the Fat Controller.
Bert swears petty revenge when a pair of clergymen visiting the island accidentally splash him with mud with their car.
When Duck's whistle begins to make funny noises, the other engines make fun of him and Mike gets so angry that he blows his safety valve.
CGI animated escapades. Mike complains that the miniature railway is not taken seriously, but an opportunity arises for them to carry wool to market.
Henry is very excited as it is time for him to be repainted. But the Steamworks is very busy, and Kevin grabs some cans of luminous paint by mistake for Henry's paint job.
Thomas, Percy and Toby hear something underneath a bridge near the watermill that makes them believe a troll could be living there.
The engines are startled by a rail zeppelin who they believe will eventually replace them, which makes them worry about their possible futures.
When a zeppelin comes flying over Sodor, Hugo is convinced that he is meant to fly too. But try as he might, he can't get off the ground.
Ryan takes Judy and Jerome to Arlesburgh Harbour for a change, but when Thomas goes looking for the breakdown train, it is nowhere to be found!
When Skiff overhears Sir Topham Hatt talking about a mermaid at Sodor's maritime museum, Skiff goes out to sea with Sir Topham Hatt and gets into trouble.
While Marion is working on Thomas' Branch Line, she hears a strange voice and thinks she has found a talking Christmas tree, but no one believes her.
Stephen, the old engine at the castle, is jealous when Glynn, the old coffeepot engine, is restored and brought to Ulfstead Castle.