PM Morna works as a cleaner for well-off families in Edinburgh. She spends her time drinking mostly, attempting affairs and trying to work out the mind of her 20 year old son with whom she shares her Dalry flat. Athol, her elder brother by 2 years, lives near Glasgow airport with his wife Evelyn. The owner of a floor tiling company, with two grown up children, he's proud of his hard-won achievements since moving West years before. Like any brother and sister they have fond and not-so fond memories of their upbringing, differing views on their parents and definite opinions about each other. Especially so in their case since Morna and Athol haven't spoken to each other in fourteen years... When Morna's son Joshua travels west to make contact with Athol he sets off, for all of them, a remarkable and life-changing series of events.