Thomas & Friends (1984)

S7E11 Bad Day At Castle Loch

The historic Scottish castle is set to welcome visitors again, exciting Donald and Douglas. However, whispers of a creature dwelling in the nearby loch begin to circulate, but the twins scoff at the tales. One fateful evening, they find themselves stranded close to the castle, and soon, an ominous shape emerges from the depths of the water, heading right for them…