Whether caused by small things such as a cup of coffee and a book, or major events such as Stuart's application for promotion and his wife Irene's decision to go off and study for a PhD in Aberdeen, change is coming to serial fiction's favourite street. But for three seven-year-old boys - Bertie Pollock, Ranald Braveheart Macpherson, and Big Lou's foster son Finlay - it also means a getting a glimpse of perfect happiness.
Alexander McCall Smith's delightfully witty, wise and sometimes surreal comedy spirals out to include tennis-playing Rwandan Forest People, researches into levitating Celtic saints, bogus headhunters in Papua New Guinea and primary school performances of Beckett. But its heart remains where it has always been - true to life, love and laughter in Edinburgh's New Town.