Glasgow: a Maryhill housing estate, home of John, his young brother, mother Lizzie and father Dan. John wakes early, softly singing a Northern Irish Protestant song.
John dresses for the Protestant parade; Lizzie is very proud, Dan amused. John's bus journey to Muirhill Flute Band's headquarters, parade uniform mostly hidden by Dan's coat, is good-natured enough. He meets Rab, the order/lodge leader there. Rab greets him warmly and they prepare for the parade.
After a talking to by a senior lodge leader Rab takes the band's place in the street and the band set off. Amidst the deafening noise of the drums and flutes we first see John and the other mace throwers leading their bands, moving and throwing the maces twisting into the air.
By midday the bands and the crowds reach a large park. Alcohol is everywhere as people half-listen to sectarian speeches in the warm sun, clapping afterwards. A Catholic man is suppressed in the crowd.
The sky turns to grey as John's band reform, under Rab's invitation, for the unofficial march through a Catholic residential area known to them as Fenian Alley: Duncan Street, a narrow street of high, old tenements. The band march into the wet, grey walls and stop halfway through. The band incite the Catholic residents to violence, leading to a far more violent, orchestrated retaliation by Rab and his friends.
John returns from Duncan Street shocked and disturbed. He meets Dan who in a face-to-face encounter with Rab is challengingly critical of Rab. John and Dan go to a spare, local pub. Later Dan becomes very drunk but urges John to go to the friends that he has promised to meet in a Catholic pub. John leaves and meets his friends, including Paddy, who is jovial and philosophical about the troubles.
John is recognised from Duncan Street by a man spoiling for revenge for the violence to his brother there. The moment is dealt with by Paddy but the man waits for John outside and a fight quickly develops when the friends leave the pub. When Paddy is stabbed the friends are forced to overcome the man. The friends scatter, chased by the police. John evades the police but is head butted by a confused drunk on the way home.
Returning home, disillusioned, he has a long conversation with Dan, who has sobered-up, on Glasgow and their desires and reasons to leave or stay. Lizzie, overhearing, is angry with Dan. John goes to bed troubled, but as he fades into sleep his face changes to a smile as he sees images of the mace, twisting through a blue sky.
