Thomas and the Shadowy Night is a "play-a-sound" book.
Throughout the book, readers are able to interact with the pages, making sounds and shining the flashlight onto the page to make out shadows.
Percy is unable to pull his mail train, so Thomas is given the job. He boasts about this to Gordon and James, who warn him about the shadowy path he will have to puff through. Thomas dismisses their warnings, claiming he is not scared of shadows.
Soon Thomas reaches the forest that James warned him about. He is sure he is not scared, but then hears another engine's whistle. Thomas becomes scared since there are not any other engines around and he does not know who made the whistle.
Trying to convince himself it was nothing, Thomas quickly puffs away, especially when he hears the strange whistle again. He comes to a tunnel, where he sees a silhouette of a man inside. Thomas becomes scared again, even though the man is made through a strange hole through some cobwebs.
Thomas soon finds Rocky on the line, right next to what appears to be a big ghost engine. Thomas asks Rocky if he had heard a whistle, to which Rocky replies that he had only heard Edward, who had brought him there. Thomas, concludes that he was hearing Edward's whistle all along.
Thomas completes his mail run on time, and returns to the sheds. Thomas tells Gordon and James that he was scared, but kept on going. Sir Topham Hatt is proud of him and praises him for being brave and really useful. When he leaves, the engines fall fast asleep for the night.
The name of the line in which Thomas goes down is unknown.
- In the first illustration, Thomas' face is too big and his bufferbeam is too small.
- Because of how the book is designed, some tracks of the pop-up sections do not align with the ones on the page.
- It is said that Thomas was pulling the mail train, but he has no mail trucks at any point in the story.
- Tidmouth Sheds only has three berths and no turntable.