If only Pat Macgregor had an inkling of the embarrassment - romantic, professional, even aesthetic - that flowed from accepting narcissistic ex-boyfriend Bruce Anderson's invitation for coffee, she would never have said yes. And if only Matthew, her boss at the art gallery, hadn't wandered into his local bookshop and picked up a particular book at a particular time, he would never have knocked over his former English teacher or attracted the attentions of the police.

With his characteristic warmth, inventiveness and brilliant wit, Alexander McCall Smith gives us more of the gloriously entertaining comings and goings at 44 Scotland Street, the Edinburgh townhouse. Six-year-old prodigy Bertie perseveres in his heroic struggle for truth and balanced good sense against his insufferable mother and her crony, the psychotherapist Dr Fairbairn, going as far as to make a short-lived bid for freedom on a trip to Paris with the Edinburgh youth orchestra.

Even down to its well-set Georgian townhouses, Edinburgh is a hymn to measure and harmony. But on Scotland Street, domestic accord is in short supply. Matthew and Elspeth welcome three new arrivals, though the joys of multiple parenthood are somewhat lost due to sleep deprivation and the difficulties of telling their brood apart. Angus and Domenica are to marry, and Domenica has ambitious and disturbing plans for their living arrangements, especially when it appears that Antonia, in Italy recuperating from Stendhal Syndrome, may not return.

Scotland Street witnesses the wedding of the century of Angus Lordie to Domenica Macdonald, but as the newlyweds depart on honeymoon Edinburgh is in disarray. Recovering from the trauma of being best man, Matthew is taken up by a Dane called Bo, while Cyril eludes his dog-sitter and embarks on an odyssey involving fox-holes and the official residence of a cardinal. Narcissist Bruce meets his match in the form of a sinister doppelganger; Bertie, set up by his mother for fresh embarrassment at school, yearns for freedom; and Big Lou goes viral.

As summer blooms in Edinburgh's gardens and Bertie Pollock's birthday appears on the horizon, all at 44 Scotland Street is not cake and sunshine. Newlywed Angus Lordie has been booked by his bride into what he must not call the loony bin; Bruce's first encounter with hot wax brings more anguish than he bargained for; and Bertie's birthday dreams of scout camp and a penknife look set to be replaced by a game of Royal Weddings and a gender-neutral doll.