'Do not open - destroy.' The words on the envelope he has found are written in Kath's hand, but Glyn ignores his wife's instruction and breaks the seal. His life unwinds. For he finds a photograph showing Kath holding hands with another man. Unable to forget this long-ago act of betrayal he recklessly excavates the past, seeking out who knew what, tearing apart other lives as he tries to dig up the roots of his wife's infidelity. But what is the truth about Kath? What is the truth about their love? And can it survive this?