Stuck in the Mud is a Step Into Reading book.
Thomas was puffing down the tracks when he saw an abandoned engine named Hiro. Hiro asked Thomas not tell Sir Topham Hatt about him for fear of being scrapped. But Spencer chuffed by, saw Hiro, and said he was going to tell the Fat Controller. Thomas raced to stop Spencer across an old bridge and Spencer fell in the water. Thomas tells Sir Topham Hatt about Hiro and he sent Hiro to the Sodor Steamworks. After Hiro was mended, he helped rescue Spencer. Spencer thanked Hiro, and the three engines steam down the tracks.