Air date: March 16, 2011 (UK), May 8th, 2011 (US)
One very foggy day on Sodor, the Fat Controller arrives at the sheds and tells all of the engines to stay at Tidmouth Sheds as the fog is too thick. He then goes on to tell Spencer, who is visiting Sodor with the Duke and Duchess, that he can stay in Percy's berth until the little engine gets back from delivering the mail. Spencer decides that he is too grand to stay at Tidmouth Sheds and sets off for the Duke and Duchess' summerhouse, certain that he will not get lost in the thick fog.
Soon Spencer can see what he thinks is a building ahead. He is sure it is the summerhouse, until he hears Mavis. He moves closer to discover that the "building" is actually a slate wall at the quarry. Embarrassed, Spencer heads off and can soon see what he believes to be the platform at the summerhouse. Then he sees Whiff and, on closer inspection, he discovers that the "platform" is actually the rubbish crusher. Finally, he sees some tall windows which he believes is the summerhouse. But Spencer hears Thomas and he discovers that he is back at Tidmouth Sheds. Spencer feels very silly and Thomas kindly says that he can still wait with them at Tidmouth until the fog clears. Spencer feels ashamed and tells Thomas that he does not deserve the other engines' company. Then Spencer notices that Percy's berth is still empty. Thomas tells Spencer that Percy is still out with the mail and Gordon says that they are worried about him. Spencer sees an opportunity to make amends with the engines and sets out into the fog to find Percy.
Finding Percy proves harder than Spencer thought it would, until he hears a distant whistle. He chuffs on and the whistle gets louder and louder until he finds Percy who is lost in the fog. Buffer-to-buffer, Percy and Spencer head back to Tidmouth Sheds, guided by Thomas' whistle. When they arrive, the engines toot happily and Percy invites Spencer to stay with them for a while, to which Spencer delightfully agrees.
This episode contains examples of:
- A Day in the Limelight: For Spencer.
- Pet the Dog: Spencer is humbled after getting lost in the fog, and helps Percy make his way back to the sheds.
