Donald and Douglas like Castle Loch, as it reminds them of their old home in Scotland. They are instructed to take a special load for its special reopening. Douglas teases Percy about a possible monster, and he and Donald get into an argument. Disaster strikes when a fallen tree and landslide leave them stranded all night, leaving the twins to worry about the monster.

Salty collects Fergus from the Smelters. On the way home, Salty and Fergus come across the Lighthouse, with its generator broken down, which endangers a ship out at sea.