It is the Edinburgh Festival. People queuing for a lunchtime show witness a road-rage incident - an incident which changes the lives of everyone involved.
Jackson Brodie, ex-army, ex-police, ex-private detective, is also an innocent bystander - until he becomes a suspect.
With Case Histories, Kate Atkinson showed how brilliantly she could explore the crime genre and make it her own.
In One Good Turn she takes her masterful plotting one step further.
Like a set of Russian dolls each thread of the narrative reveals itself to be related to the last.
Her Dickensian cast of characters are all looking for love or money and find it in surprising places.
As ever with Atkinson what each one actually discovers is their true self. Unputdownable and triumphant, One Good Turn is a sharply intelligent read that is also percipient, funny, and totally satisfying.