- “What's a Santa Claus?"
"Santa Claus is someone who drops presents down chimneys during Christmas time."
"I wonder if..."
"No! Chimneys, Percy! Not funnels!”
- ―Percy and Thomas talking about Santa Claus in the UK version
Thomas and Percy's Christmas Adventure, retitled Thomas and Percy's Mountain Adventure in North American releases, is the twenty-sixth and final episode of the third series.
Christmas (UK) Version
Thomas is heading towards the small town called Ulfstead to greet the visitors. One December morning, Thomas announces that Christmas is near and promises to bring them plenty of parcels. That night, however, an early snowstorm arrives and Thomas is given an extra mail van. Percy is unhappy that he cannot help, but his chance comes when Thomas is forced to give Percy his job in favour of another. Thomas is not pleased with the change, but Percy is delighted and sets off.
As he makes his way to the village, a man flags him down. He explains that the village is snowed under. Thomas and Percy work together to save the villagers, and Harold and Terence join in; Terence clears the snow, and Harold drops food supplies for them. They call the team the best Santa Claus the village has had, which confuses Percy. Thomas explains that Santa is a man who brings gifts through chimneys. Percy looks at his funnel, and though clearing up the confusion, Thomas remembers that he has left his parcels in a siding.
That night at the village, Henrietta is loaded up with paint pots and parcels and Toby sneaks her along with the villagers on board into the yard. When the engines wake up, they are surprised to find the sheds decorated with parcels. They all agree that it is the best Christmas they have ever had.
Thanksgiving (US) Version
Thomas is heading towards the small town called Ulfstead to greet the visitors. One day, Thomas announces that Thanksgiving is near and promises to bring them plenty of parcels. That night, however, an early snowstorm arrives and Thomas is given an extra mail car. Percy is unhappy that he cannot help, but his chance comes when Thomas is forced to give Percy his job in favor of another. Thomas is not pleased with the change, but Percy is delighted and sets off.
As he makes his way to the village, a man flags him down. He explains that he village is snowed under. Thomas and Percy work together to save the villagers, and Harold and Terence join in; Terence clears the snow, and Harold delivers their Thanksgiving dinner. Thomas then remembers that Percy has left his parcels in a siding.
That night, Toby and Henrietta load up paint pots and parcels and sneak into the yard. When the engines wake up, they are surprised to find the sheds decorated with parcels. They all agree that it is the best Thanksgiving they have ever had.
- Henrietta (does not speak)
- Sir Topham Hatt (does not speak)
- Edward (cameo)
- Henry (cameo)
- Gordon (cameo)
- James (cameo)
- Duck (cameo)
- Donald (cameo)
- Annie and Clarabel (cameo)
- Bertie (cameo)
- Jeremiah Jobling (cameo)
- Mrs. Kyndley (cameo)
- Farmer Finney (cameo)
- Harold's Pilots (cameo)
- Big Mickey (faceless; cameo)
- Father Christmas (mentioned in UK dub)
- The Waterfall
- Tidmouth Sheds
- The Windmill
- Arlesburgh Harbour
- Lower Suddery
- Knapford (mentioned)
- Stock footage from All at Sea is used.
- This episode was heavily edited specifically for its airing on Shining Time Station to remove all references to Christmas and replace them with references to Thanksgiving, since the Shining Time Station episode that it aired on ("Billy's Party") was a Thanksgiving-themed episode. The conversation in which Percy asks Thomas who Santa Claus is was also removed from the US version entirely. As a result, the re-synced US version is the shortest episode to date, running at 4 minutes and 12 seconds. The US release is also the first series finale to not be Christmas-themed.
- A deleted scene that shows Thomas passing the windmill in this episode was later used in the sixth series intro.
- This episode marks the last appearance of Arlesburgh Harbour until Sodor's Legend of the Lost Treasure.
- The last broadcast of this episode's UK version in Australia was Christmas Eve 2003 on ABC.
- This is one the two episodes from the third series that were originally written by Britt Allcroft and David Mitton, the other being All at Sea.
- This was the final episode to air on CiTV until No Sleep for Cranky on 6th January 2003.
- This is the final episode narrated by Radovan Vaculík in the Czech Republic, János Bata (for Minimax) and József Kerekes (for JimJam) in Hungary and Pedro D'Aguillón Jr. in Latin America (for Shining Time Station).
- Big Mickey, a fishing boat, the crawler tractor and a wooden shed from TUGS appear in the episode.
- On the end credits of the Shining Time Station episode, Billy's Party, the back cover of Thomas' Christmas Wonderland and Other Thomas Adventures, the Holiday Express DVD, Thomas & Friends Classic Volume 3 and the Roku Channel, the UK title is used.
- Harold simply drops the parcels without any parachutes, and thus some of them hit the people after bouncing on the ground.
- Because the conversation where Percy asks Thomas who Santa Claus is was removed from the US version, the narration becomes entirely out of sync with the footage, music and sound effects. In versions where the footage is properly cut to sync up with the narration, it is instead the music and sound effects that are out of sync after that point.
- A deleted scene included in the song Toby shows that the tracks in the sheds end in front of the engines.
- The exterior shots of Tidmouth Sheds show it with the usual six berths, but in the interior shots, eleven tracks are shown.
- Through most of the episode, one of Percy's lamp irons is missing.
- In the close-up of the fogman, the studio is reflected in his lamp.
- In the Japanese narration, Douglas is mentioned when it is Donald who is shown.
- When James is pushing the tankers, he appears to not be wearing a face mask.
- Percy: Beep! Beep! Wake up, lazywings! The mountain villagers need your help! They're stranded!
- Harold: Whizzo! I like an emergency to keep me warm.
- [after the village is saved]
- Villagers: Well done, Percy! Well done, Thomas! You're the best Santa Claus this village has ever had!
- Percy: What's a Santa Claus?
- Thomas: Santa Claus is someone who drops presents down chimneys at Christmas time.
- Percy: [looks up at his funnel] I wonder if...
- Thomas: [laughs] No! Chimneys, Percy! Not funnels! Which reminds me, your mail train is still back at the siding. Isn't it?
In Other Languages