Thomas plays a trick on Rheneas by whistling beside him, making the little engine knock his trucks of pilings. The other engines want to join in and surprise Rusty, Sir Handel, and Peter Sam. When Mr. Percival finds that none of Thomas' trucks have been loaded, he is furious. Thomas, seeing the error of his ways, works to get everything in order, but plays one last trick on Mr. Percival and hides his trucks. When Mr. Percival discovers the trick, he declares that Thomas is "a very funny engine".
