Sunshine on Leith is based on the sensational stage hit of the same name, featuring music by pop-folk band The Proclaimers. The film follows the stories of lifelong best pals Davy (George MacKay) and Ally (Kevin Guthrie), who have returned home to Edinburgh after a tour of duty in Afghanistan. After having survived a road mine explosion that killed or maimed several comrades, the lads have to get back to the everyday business of finding work. Ally reunites with Davy’s sister Liz (Freya Mavor), though his hopes for a conventional domestic future together don’t mesh with her hunger to “see the world.” She sets Davy up with her hospital co-worker Yvonne (Antonia Thomas), a recent London transplant, and they hit it off pretty well.
Meanwhile, the siblings’ parents (Peter Mullan, Jane Horrocks) are about to celebrate their 25th wedding anniversary, though Dad’s discovery that he has a previously unknown adult daughter by another woman throws their marriage into sudden turmoil. Just as all three women are on the outs with their men, a conveniently timed medical crisis brings everyone back to their senses.