Ted, Dougal, Jack, and Mrs. Doyle depart Craggy Island for the mainland for various reasons; Ted plans to collect £200 he won in a bet, and then visit the "Very Dark Caves" with Dougal, Mrs. Doyle plans to meet with her friend Mrs. Dineen to have tea, and Jack needs to go to the optician to get a new pair of glasses, after his last pair was stolen by a crow.
Ted is surprised to see Richard Wilson, from the sitcom One Foot in the Grave, waiting outside, and goes up to greet him with his catchphrase "I don't believe it!".
Ted and Dougal end up finding Father Noel Furlong and the St. Luke's Youth Group deeper within, having been lost there for two days.
After Noel decides to have a screeching competition and is buried under a pile of falling rocks (while the Youth Group members leave and board flights to Paraguay), Ted and Dougal continue on their own.
Ted eventually discovers that Dougal's tank top has come unravelled, and realises that the thread will provide a way out, but after inadvertently winding it all up in the excitement, he again exclaims "I don't believe it!
Ted is initially ready to let them stay, but when Dougal tries to get his attention, loses his temper and pays the money he won in the bet.