After being teased, Thomas is determined to prove to Cranky that he can carry more than light loads.
It's the day of the Spring Party at the Duke and Duchess of Boxford's summer house. Cranky teases Thomas that he can only carry light loads. Thomas is outraged by this and determines to prove to Cranky that he is not "Tiny Thomas". First he borrows James' and Henry's heavy loads. Cranky lifts both, but with a lot of creaking and cranking. So Thomas decides Cranky should lift something heavier - himself!. It's too heavy for Cranky and he breaks! Sir Topham Hatt is very cross. Thomas then asks Spencer to take the heavy loads to the party at the summer house while he rushes to the Sodor Steam Works to get parts for Cranky. Once Cranky was fixed, he and Thomas have a party together at the Docks! Thomas has a special Special. He is to take Sir Topham Hatt to his special birthday party. But when Thomas goes to pick him up at Maithwaite, he doesn't look like Sir Topham Hatt at all!! He has a moustache! Things get worse as the imposter Sir Topham Hatt demands to go to the Whispering Woods where he encourages children to play. Then he stops at a junction and rushes into the signal box to have a turn at throwing the levers. As a result, Gordon hurtles down a branch line! When Thomas arrives back at Maithwaite, he realizes this isn't Sir Topham Hatt! The imposter reveals himself as Sir Topham Hatt's brother - Sir Lowham Hatt!