"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 and causes Noel to be covered in rocks. The youth group quickly flees to Paraguay, and Ted and Dougal leave Noel when he immediately starts to get annoying again.
In the tearoom, Mrs. Doyle and Mrs. Dineen spend the afternoon gossiping about their friends but get into a violent fight when neither will let the other pay for the drinks.
Ted discovers that Dougal's jumper has been unraveling and intends to follow the thread out, only to pull in the thread instead of following it. Ted screams in frustration "I don't believe it!", only for the words to echo through the caves and back to Richard Wilson, who thinks he's going mad. After spending hours wandering, Ted and Dougal finally get out and go for something to eat only to be informed that Jack, Mrs. Doyle and Mrs. Dineen have all been arrested. Going to the station, Ted is told by a policeman that he needs to either pay £200 or leave the three in the cells for the night. Ted starts to tell the policeman that it may be for the best to leave the three behind bars, but when Dougal tries to attract Ted's attention, Ted reluctantly hands over the £200 and furiously berates Dougal for trying to remind him about the money and embarrassing him. Dougal replies that he forgot all about the money and was just trying to tell Ted that his fly was open.
Returning to Craggy Island, Ted promises to never return to the Mainland unless it is necessary... which, unfortunately, it always is. Meanwhile, Richard Wilson gets lost while bike-riding and coincidentally winds up outside the parochial house. When he knocks on the door and Ted answers, Wilson exclaims "I don't believe it!"
After the credits, we see Noel still trapped under the pile of rocks singing "Fat Bottomed Girls" to himself.Richard Wilson make a special guest appearance as himself, with Ted and Dougal recognising him as "yer man from One Foot in the Grave". In the episode, every time Ted says, "I don't believe it", Wilson becomes very angry (to the point where he violently attacks Ted). This is a reference to the fact that Wilson really does hate people going up to him and saying his catchphrase from One Foot in the Grave and only performs the line for charity events. The situation was conceived when Father Ted writers Graham Linehan and Arthur Mathews sat behind Wilson at a performance of Le Cirque du Soleil at the Royal Albert Hall. They considered how "tasteless and wrong" it would be to lean forward to him every time that an acrobat did a stunt and yell the catchphrase, and then they realised that that's exactly what their fictional priests would do.
Graham Norton returns for his third and final appearance as Father Noel Furlong. He sings the Queen songs "Bohemian Rhapsody" and, at the very end of the episode, "Fat Bottomed Girls".
Art director Bill Crutcher appears in a cameo as the smoking bin man.