Yvonne Carmichael has worked hard to achieve the life she always wanted: a high flying career in genetics, a beautiful home, a good relationship with her husband and their two grown up children. Then one day she meets a stranger at the Houses of Parliament and, on impulse, begins a passionate affair with him, a decision that will put everything she values at risk. At first she believes she can keep the relationship separate from the rest of her life, but she can't control what happens next. All of her careful plans spiral into greater deceit and, eventually, a life changing act of violence.