The Great Discovery (2021 Film) is a Thomas & Friends movie special released in 2021.


The railway is preparing for Sodor Day and Thomas and James are racing to the wharf to be given a special job by Mr. Percival. Thomas wins and is sent into the hills to collect lumber with Duncan. After Thomas teases Duncan, Duncan pays Thomas out by sending him on an old, disused line which he claims will lead Thomas back to the wharf faster. 

After avoiding an old, collapsing bridge, Thomas takes another route at the old junction and as he journeys further down the line, he comes across an old overgrown town.

The news of Thomas' discovery spreads and eventually reaches the Fat Controller, who tells Thomas that the town is Great Waterton - the largest town on Sodor when steam engines first came to the island. The Fat Controller decides that the restoration of the legendary lost town would be perfect for Sodor Day and calls the Pack to help. Thomas is told to take charge of the engines working around the town, while Thomas's friend from India, Ashima is brought to do Thomas' regular jobs.

All of the engines, including Thomas, take to Ashima, who does a good job and has fun as well, but when Diesel sees Ashima doing Thomas's jobs and fraternising with his friends, he becomes jealous. Thomas is surprised when Ashima takes his place at Tidmouth Sheds and the final straw comes when Ashima takes his place as the leader of the restoration project after Thomas has an accident.

Later, Thomas is shunting stone trucks for Ashima to take away when Diesel decides to make Ashima look silly by giving her a train too heavy for her to pull and Thomas becomes worried. Unfortunately, the plan backfires - as Ashima ascends the hill, a coupling breaks and the trucks race down the hill, veering into a siding and crashing into the newly finished tower. The Fat Controller states that this will likely set back the restoration past Sodor Day and Diesel gets blamed. Stanley, however, realises that Thomas merely missed his friends and wants to set things right. Later that night, Thomas decides to clear the rubble out of the way. He is almost finished when he accidentally bumps a truck into an old mine shaft. Racing in after it, Thomas crashes into a blocked tunnel and falls down into the water where he floats down an underground waterway.

After the engines meet at Great Waterton, Stanley arrives with Dory, Marlin and Nemo and asks where Thomas is and the engines soon realise that Thomas is missing. The Fat Controller organises a search effort and everyone searched everywhere, but no one could find Thomas. They were just about to give up, when Percy and Stanley reminds them that Thomas found Great Waterton on his own, stating that it is his town and that they cannot have the opening without him and everyone agrees. Dory thinks Thomas ran away after the incident yesterday and Ashima, Dory, Marlin and Nemo tries to find him in the hills. Meanwhile, Thomas continues floating in the dark tunnel until he reaches an opening to the mine and is flung across a canyon and down a hill without the wooden planks that made him float into the mine. Ashima, Dory, Marlin and Nemo decide to make another search effort by himself before he returns to work. Thomas, with the last of his steam, sounds a loud, long whistle. The foursome hear it and hurry to where Thomas is stranded beside the track. Thomas apologies to Ashima for what happened with the tower. Ashima tells Thomas and she pulls him back onto the rails, but the strain is too much for Ashima and a valve bursts. Thomas, using some of Ashima's coal, pushes her back to Great Waterton. The word soon spreads that Thomas has been found.

The standpipe is rebuilt, completing the restoration. As a sign of friendship, Thomas offers Stanley his last job - bringing the mayor to the festivities at Great Waterton. The engines gather at the town for the celebration and Thomas realises just how important his friends are.


  • Thomas
  • Edward
  • Henry
  • Gordon
  • James
  • Percy
  • Toby
  • Duck
  • Bill and Ben
  • Harvey
  • Emily
  • Arthur
  • Salty
  • Skarloey
  • Rheneas
  • Sir Handel
  • Rusty
  • Duncan
  • Mighty Mac
  • Freddie
  • Bertie
  • Trevor
  • Harold
  • Cranky
  • Jack
  • Alfie
  • Oliver
  • Ned
  • Buster
  • Madge
  • Stanley
  • Ashima
  • Nia
  • Rebecca
  • Diesel
  • Sir Topham Hatt
  • Lady Hatt
  • Stephen Hatt
  • Bridget Hatt
  • Miss Jenny
  • Mr. Percival
  • The Mayor of Sodor
  • Dory
  • Marlin
  • Nemo
  • Peter Sam (does not speak)
  • Annie and Clarabel (do not speak)
  • Rocky (does not speak)
  • Terence (does not speak)
  • Max and Monty (do not speak)
  • Rosie (cameo)
  • Whiff (cameo)
  • Mavis (cameo)
  • 'Arry and Bert (cameo)
  • Diesel 10 (cameo)
  • Dennis (cameo)
  • George (cameo)
  • Butch (cameo)
  • Elizabeth (cameo)
  • Carly (cameo)
  • Big Mickey (cameo)
  • Jem Cole (cameo)
  • Refreshment Lady (cameo)
  • Cyril the Fogman (cameo)
  • Lord Callan (cameo)
  • Sodor Brass Band (cameo)
  • Farmer Finney (cameo)
  • The Storyteller (cameo)
  • Kuffy the Clown (cameo)
  • The Dairy Manager (cameo)
  • Two members of the Railway Board (cameo)
  • Tinky Winky (cameo)
  • Dipsy (cameo)
  • Laa-Laa (cameo)
  • Po (cameo)
  • Henrietta (music video cameo)
  • Kelly (music video cameo)
  • Allicia Botti (mentioned in newspaper)


UK, AUS and NZ

  • John Hasler as Thomas and Rheneas
  • Keith Wickham as Edward, Henry, Gordon, Salty, Harold, Harvey, Skarloey, The Fat Controller, The Thin Controller
  • Rob Rackstraw as James and Toby
  • Nigel Pilkington as Percy and Trevor
  • Teresa Gallagher as Emily and Madge
  • Matt Wilkinson as Cranky, Jack, Rusty, Ben and Mighty Mac
  • Tim Whitnall as Oliver the Crane and Buster
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