Yvonne Carmichael, a renowned geneticist, public authority and mother of two, has become involved in an affair. So thrilled and absorbed is she in her newfound sexual power that she fails to notice the real danger about to blindside her from a seemingly innocuous angle. Then, reeling from an act of violence, Yvonne discovers that her desire for justice and revenge has already been compromised. Everything hinges on one night in a dark little alley called Apple Tree Yard.