"The Mainland" is the fourth episode of the third series of the Channel 4 sitcom Father Ted and the 21st episode overall. It was first broadcast on 3 April 1998.

As Dougal finishes watching an episode of One Foot in the Grave, Ted informs him that they are travelling to the mainland to collect £200 that Ted won in a bet, and Dougal persuades him to visit some local caves as well. Meanwhile Jack is also going in order to get some new glasses (due to birds constantly stealing them) while Mrs. Doyle is going for tea with her friend Mrs. Dineen. Upon arriving, Mrs. Doyle and Mrs. Dineen are left at a tea house, Jack is left at the optometrist's, and Ted and Dougal collect Ted's winnings then go visit the Very Dark Caves.

While waiting outside the caves, Ted spots Richard Wilson standing nearby and, thinking that he'll love it, walks up to him and screeches "I don't believe it!" – Wilson's catchphrase from One Foot in the Grave. However, Wilson begins to beat Ted up in anger and has to be dragged off by others as he shouts to Ted, "I'll bloody kill you!"

Meanwhile, Jack gets some new glasses only for them to be immediately stolen again by a bird. Fumbling along the street looking for alcohol, Jack accidentally wanders into an Alcoholics Anonymous meeting, with everyone assuming his screams of "Drink!" to be a cry for help. Later, Jack finally makes it into a pub and buys a bottle of whiskey, only for one of the people at the meeting to try and stop him, earning a trip in an ambulance doing so.

During the tour of the caves, Ted learns that the caves are 15 million years old and casually says "I don't believe it", only to find he was standing behind Richard Wilson, who attacks Ted again. Ted and Dougal flee down another cave, and a hungry Dougal - who realized earlier that he forgot to eat any breakfast - begins to hallucinate and sees Ted as Abraham Lincoln. Ted and Dougal are soon approached by someone under a sheet pretending to be a ghost - who turns out to be Father Noel Furlong, who along with his St. Luke's Youth Group have been trapped in the caves for two days. After mangling "Bohemian Rhapsody" and joking about having to eat a member of his group (driving everyone crazy as usual), Noel decides to have a screeching competition - which causes a cave-in that leaves Noel buried in rocks. The youth group quickly flees to Paraguay, and Ted and Dougal leave Noel when he immediately starts to get annoying again.

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