A secret wife. A secret life. A killer who knows.
William and Mary have been married sixty years. William is a celebrated surgeon, Mary a devoted wife.
William and Olivia have been together twenty years. Olivia was once a tennis star, but her career has long since faded.
Clinical psychologist Joe O'Loughlin knows only one of these stories to be true. But when he is called to his father's hospital bed after a brutal attack, everything he once knew is turned upside down.
Who is the strange woman crying at William's bedside, covered in his blood - a friend, a mistress, a fantasist or a killer?