Sir Topham Hatt is away on holiday, leaving Mr. Conductor in charge. Meanwhile, in Shining Time, Mr. Conductor's supply of gold dust is running low and not enough to allow him to travel back from Sodor. Later that day, at Tidmouth Sheds, Diesel 10 arrives and announces his plan to get rid of the steam engines; Thomas leaves to get Mr. Conductor. "The Lost Engine", named Lady, is hidden in a workshop on Muffle Mountain, as done by Burnett Stone after Diesel 10's last attempt to destroy her. Despite having rebuilt Lady, Burnett is unable to steam her despite using different types of coal. At night, Diesel 10 attacks the shed where the steam engines are sleeping, but after his gold dust fails him, Mr. Conductor repels him with sugar.