A Quiet Day in Belfast is a 1974 Canadian drama film set in Northern Ireland and starring Barry Foster, Margot Kidder and Sean McCann.

Charlie McLarnon, a Protestant Northern Irish dog breeder, has been training and fasting his greyhound "Duke of Donegal" in preparation for a race.

John Slattery is a middle-aged, single Catholic Northern Irishman who manages a betting shop in Belfast.

John lives at home with his mother and his younger sister Brigit Slattery, who has a British soldier for a boyfriend.

The soldier and his comrades are stationed nearby to keep the peace in the neighborhood, armed with tear gas and shields, while local boys regularly hurl rocks and insults at them.

Peter O'Lurgan, a Catholic serial bomber wanted by the authorities, is a friend of John's and a hero of Tim's.

On this day he imposes on John to use the betting shop as a safe house to work on a pair of bombs and enlists Tim's aid in planting them.

Brigit has an identical twin sister, Thelma, who married and emigrated to Canada years ago and has recently returned to visit the family.

The "Duke of Donegal" has won the race and most of the punters who bet on the dog promptly return to the shop to collect their winnings.