Diesel's Ghostly Christmas is a double length episode from the Nineteenth season of Thomas and Friends.
One day at Knapford Station, Thomas is preparing to take a group of singers to their rehearsal as well as take a goods train up to Ulfstead Castle for the Earl's Christmas lunch, when the Fat Controller approaches him, telling him that he must be at Brendam Docks, but has twisted his ankle and can't drive. Already busy with his current jobs, Thomas decides to ask one of his friends if they could take the Fat Controller to the Docks instead. He finds Diesel in the yard and asks him if he could do it, but Diesel says that he's busy and oils away. When Emily arrives, Thomas asks her instead, and she's more than happy to oblige.
At Brendam Docks, Cranky is swinging a large Christmas tree about and orders Salty to help, but as his fuel line is frozen, Salty cannot help. When Diesel arrives at the Docks, Cranky orders him to push the flatbed under him, but Diesel says that he's too busy. Salty's engine roars to life and he rushes over to Cranky, but the tree lands on top of him. Cranky scolds Diesel for not helping out, but Diesel simply dismisses it. Though Salty tries to tell Diesel that Christmas is a time for good will, Diesel scoffs at it. As Diesel leaves, Thomas also arrives at the Docks and glares at him.
When the tree is finally lifted onto a flatbed, Paxton arrives to take it to Ulfstead Castle, but has trouble trying to pull it. Thomas suggests that Diesel can help, but Diesel refuses to do so. When Paxton does set off at last, the chains holding the tree down weaken and snap, and the weight of the tree tipping over makes Paxton derail at a bend. Hours later, Diesel passes by, but refuses to help Paxton. Shortly after that, Thomas arrives, noticing that the tracks became damaged in the accident. He asks Paxton if that was Diesel who just passed by, which Paxton confirms. Thomas thinks of a plan to get back at Diesel.
That night at the Dieselworks, the mist comes down. Diesel anxiously enters the workshop, when all of a sudden, lights come on, and Emily, hanging from chains and pretending to be 'E-Marley's Ghost', appears, telling Diesel to stop being an unhelpful engine. She tells him that he will be visited by three more ghosts, and that he must go to the Docks, otherwise he will end up in "big trouble!!!!". Diesel leaves the Dieselworks in fear, and Emily and Thomas laugh at the success of his plan.
When Diesel arrives at the Docks, he doesn't find the Fat Controller, but does hear a ghostly voice. He tries to get away, but is stopped by Salty, who is covered in a fishing net and surrounded by lights. Salty, pretending to be the 'Ghost of Christmas Past', tells Diesel about many of his past mistakes, such as the time he pushed trucks of china clay into the sea, and when he spilled milk all over the Fat Controller, and when he refused to help with the tree. Diesel, too scared to hear anymore, runs away, and Cranky and Salty laugh.
Diesel soon stops close by to a bridge and reassures himself that he must have been hearing things, but becomes frightened when bright lights emerge from the bridge, followed by a ghostly voice. Paxton, covered in lanterns and speaking through pipes on a flatbed, introduces himself as the 'Ghost of Christmas Present', but Diesel fearfully says that ghosts aren't real, to which Paxton mutters [to the audience] that he must be good at pretending. He tells Diesel that he should be out enjoying the extra jobs at Christmas, but Diesel scoffs at this and asks why he would enjoy extra work. Paxton tells him to think of the happiness of others, but as he goes on about this, Diesel runs away. Diesel is so frightened that he doesn't notice the damaged bit of track, running over it and derailing. When Thomas passes by, Diesel begs him to help, but Thomas says that he's far too busy and he has more jobs to do.
The next morning at the waste dump, Thomas orders Whiff to have a pile of rubbish dumped on him. When the rubbish is poured over him, he returns to the scene of Diesel's accident and pretends to be the 'Ghost of Christmas Future', telling him that if he does not help others, then they will stop helping him, and he'll be left alone at the scene of his accident for the rest of his life. Thomas then leaves, leaving Diesel to feel very afraid.
At Ulfstead Castle, the Earl is preparing for the Christmas luncheon, watching as Percy, Emily and Paxton arrive with the presents, the choir, and the food. However, the guests have still yet to arrive.
Meanwhile, Thomas returns to Diesel with Rocky to have him rerailed. When Diesel is lifted up into the air, he joyfully thanks Thomas and acts unusually charismatic and excited, promising to do whatever jobs need to be done. He offers to take Rocky back to the Search and Rescue Centre, which Thomas gladly lets him do as he's already late bringing the guests to the Castle.
At Knapford, Thomas arrives and takes the guests to Ulfstead Castle, but he forgets all about the Fat Controller. When he steps out of his office, the Fat Controller calls out to Thomas, but Thomas is too far away to hear him. Later on, Diesel arrives at Knapford, when he hears the Fat Controller moaning in pain, initially believing it to be another ghost. He spots the Fat Controller and asks him if he should have been at Ulfstead Castle, which the Fat Controller confirms, but he has no way of getting there. Diesel offers to take him to the Castle.
At Ulfstead Castle, Thomas arrives with the guests, but notices that the Fat Controller isn't there. Diesel soon arrives with the Fat Controller, and the party begins. That night, Diesel, covered in Christmas lights, is overjoyed to see everybody so happy. Paxton quietly tells Thomas that his plan was a success; Diesel is now a very helpful engine. Diesel wishes everybody a Merry Christmas.
- This special is based off of the Charles Dickens novel A Christmas Carol.
- Paxton and Rocky break the fourth wall.
- The events to the third season episode "Diesel Does it Again" and seventeen episode "No More Mr. Nice Engine" are referenced.
- This is the first episode in all of Thomas and Friends to have two parts.