At 2 am on the morning of her fortieth birthday, Sophie wakes in the darkness of her bedroom and finds a stranger watching her from the foot of the bed. The intruder hands Sophie a letter and issues an ultimatum: the message is to be opened at her forthcoming party, in front of family and friends, at exactly 8 pm. Any failure to comply will not end well. Sophie can only think of one person who hates her enough to have hired a professional to menace her like this: her fiancé's ex-wife. What can the letter possibly contain? And why must it be read in front of everyone she loves? This will be no ordinary fortieth party. Sophie is not the only person holding a secret about the evening ahead. When the clock strikes eight, the course of several people's lives will be altered forever.