At 2 a.m. on the morning of her fortieth birthday, Sophie wakes to find an intruder in her bedroom. The stranger hands Sophie a letter and issues an threat: open the letter at her party that evening, in front of family and friends, at exactly 8 p.m., or those she loves will be in grave danger.

What can the letter possibly contain?

This will be no ordinary party; Sophie is not the only person keeping a secret about the evening ahead. When the clock strikes eight, the course of several people's lives will be altered for ever.

Now updated with an exclusive first chapter from Lucy Dawson's next thriller Everything You Told Me.