Toby's Discovery is the fourteenth episode ever made in Season 5.
The young Hatts make a sandcastle modeled on one in the heart of Sodor and the intrigued Fat Controller asks Toby to take him to find it. Toby finds the castle, and then visits a run-down mine located on the same map as the castle. The mines re-opened, but Toby is spooked by Thomas' tale of the "Old Warrior" who hunts in the mines during the night. Toby is horrified to be put on guard duty at the mines and meets the "Old Warrior", but discovers the ghost is really a narrow gauge engine named Bertram.
- When Toby is at the fishing village, Henrietta's roof is lifted up.