It's been years since Myron Bolitar has gotten into trouble. He hasn't had to play the hero, he hasn't used his fists - much less his gun. But all that is about to change, because of a promise...

It all starts with good intentions. Worried about his friends' teenage daughters, Myron makes them promise that if they ever get into trouble, if something happens that they can't tell their parents, they will notify him. He won't ask any questions, he'll just run to help them. And no one will know...

The call comes at two in the morning. It's Amy. She's alone in Manhattan, upset and crying. But when Myron goes to pick her up, she only tells him that she left her friends because they got drunk. And instead of going back with him, she convinces him to drop her off outside a friend's house, where she has arranged to spend the night.

The next day, however, Amy doesn't come home. She has disappeared. And the last person who saw her is Myron... An innocent promise turns into a nightmare. Faced with the suspicions of the police and Amy's parents, but above all with his own guilt, Myron must now do everything he can to find her, before it's too late...