When word reaches Jackie O'Shea (Ian Bannen) and Michael O'Sullivan (David Kelly), two elderly best friends, that someone in Tulaigh Mhór (Tullymore), their tiny Irish village of 52 people, has won the Irish National Lottery, they, along with Jackie's wife Annie (Fionnula Flanagan), plot to discover the identity of the winner. They obtain a list of lottery customers from Mrs. Kennedy (Maura O'Malley) at the post office and invite the potential winners to a chicken dinner, where they attempt to get the winner to reveal him- or herself. After everyone has left and they are no closer to an answer, Annie realizes that one person did not come to the dinner, so Jackie pays a late-night visit to the only absentee: the reclusive Ned Devine (Jimmy Keogh). He finds Ned in his home in front of the TV, still holding the ticket in his hand, a smile on his face and dead from shock. That same night, Jackie has a dream that the deceased Ned wants to share the winnings with his friends, as he has no family to claim the ticket. Jackie wakes up after the dream, and before dawn, he and Michael return to Ned's house to gather Ned's personal information so they can claim the winnings for themselves.
Elsewhere in the village, Maggie O'Toole (Susan Lynch) continues to spurn the romantic interests of her old flame, "Pig" Finn (James Nesbitt), a local pig farmer. Finn is convinced they belong together, as he thinks he is the father of her son Maurice (Robert Hickey), but she cannot abide him due to his ever-present odour of pigs. Finn has a rival in Pat Mulligan (Fintan McKeown), also hoping to marry Maggie.
Jackie and Michael call the National Lottery to make the claim, prompting a claim inspector to be sent. The inspector, Mr. Kelly, arrives to find Jackie on the beach and asks him for directions to Ned's cottage. Jackie delays Kelly by taking him on a circuitous route while Michael races to the cottage on a motorcycle, completely naked, and breaks in so he can answer the door as Ned. After discovering that the lottery winnings are far greater than they anticipated (totaling nearly IR£7 million), Jackie and Michael are forced to involve the entire village in fooling Mr. Kelly. All the villagers sign their name to a pact to participate in the ruse, except one—the local curmudgeon, Lizzie Quinn (Eileen Dromey). She threatens to report the fraud in order to receive a ten-percent reward, and attempts to blackmail Jackie for £1 million of the winnings. Jackie does not refuse her outright, but later insists to Michael, "She'll sign for the same as us, or get nothing at all!"
The villagers go to great lengths to fool the inspector, even pretending Ned's funeral is a service for Michael when the inspector wanders into the church. The inspector leaves, satisfied that the claim is legitimate, and the villagers celebrate their winnings at the local pub. Meanwhile, Lizzie makes her way to the nearest working phone, a phone box outside the village on the edge of a cliff, and phones the lottery office. Before she can report the fraud, however, the departing claim inspector sneezes while driving past her and loses control of his car, forcing an oncoming van (driven by Tullymore's village priest, returning from a sabbatical) to crash into the phone box, sending it plummeting off the cliff and crashing to the ground below with Lizzie still inside.
At the celebration, Jackie spots Maggie, who is content to marry Finn now that he CASTthe money to give up pig farming. Maggie confides in him that Ned is Maurice's real father, meaning that Maurice is technically entitled to the entire winnings. Jackie urges her to claim the fortune for Maurice, but she demurs, determined to keep the secret so that Maurice will have a father and the villagers will have their money.
Finally, Jackie, Michael, Maurice, and several other villagers stand on a headland and raise their glasses to Ned, toasting him for his gift to the village.
Ian Bannen as Jackie O'Shea
David Kelly as Michael O'Sullivan
Fionnula Flanagan as Annie O'Shea
Susan Lynch as Maggie O'Toole
James Nesbitt as Pig Finn
Adrian Robinson as Lotto Observer
Maura O'Malley as Mrs. Kennedy
Robert Hickey as Maurice O'Toole
Paddy Ward as Brendy O'Toole
James Ryland as Dennis Fitzgerald
Fintan McKeown as Pat Mulligan
Eileen Dromey as Lizzy Quinn
Kitty Fitzgerald as Kitty
Dermot Kerrigan as Father Patrick
Jimmy Keogh as Ned Devine
Paul Vaughan as Narrator
Jill Foster as car hire lady
titled Waking Ned Devine in Australia and North America