The four adult children of Mrs Flynn - Thomas (Gary Lewis), Michael (Douglas Henshall), Sheila (Rosemarie Stevenson) and John (Stephen McCole), gather at the family home in Glasgow to mourn their recently deceased mother and prepare for her funeral in the morning. In painful silence they each kiss their mother goodbye as she lies in her coffin. Following he laying-in, the four go to the local pub for a drink. Thomas gets up on stage to announce their mother's death and sing her favourite song, breaking down in the process. When DD Duncan (Malcolm Shields) and his friends find Thomas's distress hilarious, a fight breaks out between Duncan and Micahel, with the pub bouncers intervening and evicting the brawlers. Michael has been wounded in the fight. He stuffs toilet paper into his shirt to staunch the bleeding from a stab wound in his chest and leaves the pub with John. Outside he tells John what has happened and John reacts with fury vowing to take revenge.
A taxi driver refuses to take Michael to the hospital because he might bleed over his cab so Michael decides to head for a massage parlour where his friend Margaret, a nurse, works. Margaret dresses the wound as best she can and tells Michael he must go to the hospital. But Michael has a better idea. If he can hold out until morning he will go to work and pretend the injury happened there so he can claim industrial compensation. Still furious about Michael's stabbing, John storms off to find his cousin Tanga at the Chinese take-away where he works as a delivery driver. John asks Tanga where he can get a gun. Excited by the prospect of a fight, Tanga takes him to a fairground where they collect a sawn-off shotgun. Before collecting the bullets Tanga decides to re-visit Mr Bell, his last delivery customer. Tanga hates Mr Bell because he always pays by cheque and never gives him a tip.
Tanga peers through Mr Bell's bathroom window and finds him masturbating over a girlie magazine. Laughing Tanga puts the gun to Mr Bell's bare backside. In a panic Mr Bell turns around and ejaculates over Tanga's face. Outraged Tanga breaks into the house and threatens to shoot Mr Bell. Then he grabs the terrified Mrs Bell intending to rape her. John, realising that things are quickly getting out of control, struggles to get Tanga to leave the Bell house. Back in the delivery van, Tanga and John argue and Tanga makes John swear on his mother's grave that he will kill DD Duncan once they collect some bullets for the gun.
Thomas and Sheila leave the pub and go to the church where their mother's body is lying, intending to the spend the night watching over her. Sheila gets bored and accidentally topples a statue of the Virgin Mary which shatters. She leaves the church determined to make her own way home.
On the way home, her wheelchair breaks down and she is stranded as the night becomes increasingly stormy. Ten-year-old Carole happens by and tries to help Sheila but the wheelchair is too heavy for her to push and she enlists the help of some papergirls. They deliver Sheila to Carole's home where her mother Alison invites her to spend the night. The rain is lashing the city and the wind is gale force.
Michael goes to his estranged wife's house to get more bandages for his wound and to see his children. His wife, Alice returns from an AA meeting as Michael is watching his children sleep. Things are obviously still painful between Michael and Alice and although his stab wound is worsening, Michael decides to leave.
Michael goes to the Hangman's Pub for a drink and can't stop himself asking the unbelievably rude and bizarre landlord what his problem is. Hanson, the landlord, responds by grabbing Michael and throwing him into the cellar. Michael soons finds he is not alone. Others have been banished for various offences deemed serious by the landlord and it is explained to Michael that they will probably all spend the weekend in jail. Michael has no intention of spending any time in jail and devises a plan to get them all out. Hanson sees smoke coming from under the cellar door. When he opens it, the prisoners capture him and enjoy free drinks at the bar. As Michael leaves, Seamus and Henry are playing darts using Hanson's backside as a target.
The wind is howling and the rain lashing as Michael makes his weary way to the church but Thomas refuses to let him in as he has promised the priest not to open the doors to anyone, even his brother. Michael finds a side door and enters to find Thomas trying to glue the shattered statue of the Virgin Mary back together with candle wax. The brothers start arguing when Michael realises that Thomas let Sheila go home alone. Still bleeding Michael goes to find Sheila. Just as Thomas finishes mending the statue, there is a huge crack and the roof of the church is blown away. The Virgin Mary is once again in pieces and the astonished Thomas is left huddled on the floor as the storm takes its toll on the old building.
John and Tanga collect the bullets for the gun and decide to wait until morning to find and kill DD Duncan. As morning breaks and the storm abates, John finds DD Duncan and aims the gun at him. At the last second he realises that DD has a baby strapped to his front and manages to swing the gun away before it goes off.
Shocked at his own actions, John finally realises how close he has come to murder. He throws the gun to Tanga waiting in the delivery van and runs away. As Tanga struggles with the gun in the van one of DD's friends stabs him in the eye setting off the gun which shoots Tanga in the foot.
John keeps running with DD in hot pursuit. DD hands the baby to one of his friends and produces a knife. He catches up with John and as they fight John manages to get the knife away from DD and holds it to his throat. Some semblance of sanity returns and John decides not to kill DD.
Barely able to walk due to massive loss of blood, Michael manages to make his way to work. As his work mates arrive, Michael staggers out from behind some machinery claiming he has been injured and demanding industrial compensation. As he states his case he begins to lose consciousness and collapses backwards onto a discarded wooden pallet. The weight of his semi-conscious body propels the pallet into the River Clyde and he floats aimlessly down the river.
The mourners start to arrive at the shattered remnants of the church for the funeral service. Thomas is there to greet them. Carole and her mum deliver Sheila to the church in time for the service. John finally arrives during the service and finds Michael at the door. John admits to Michael that he almost killed DD Duncan and his baby. He helps Michael into the church just as Thomas is reading from the Bible. Weak, Michael collapses in front of Thomas and is carried out of the church to be taken to hospital. John lifts a crying Sheila from her wheelchair to go with Michael, and asks Thomas if he is coming too. Thomas carries on with the reading.
At the cemetary Thomas, against the advice of the undertaker, insists on carrying his mother's coffin to the grave himself. After a few steps the weight of the coffin proves too much and he falls flat on his face with the coffin on top of him. He is left lying face down in the path as the other mourners lift the coffin and carry on with the burial.
Some days later Thomas is putting flowers on his mother's grave. Michael, just released from hospital, appears at the graveside with Sheila and John. Putting the anguish of their mother's death behind them, Michael tries to reunite his brothers and sisters. After all, they are all now orphans.