The Smart family's lacklustre holiday in Norwich is turned upside down when a beguiling stranger called Amber appears, bringing with her love, joy, pain and upheaval. The Smarts try to make sense of their bewildering emotions as Amber tramples over family boundaries and forces them to think about their world and themselves in an entirely new way. The Accidental is at once a mysterious web of secret identities and a ruthlessly honest look at the silent cracks that can develop unnoticed in relationships over time.