Twelve-year-old Maddie Thompson and her friend Lana share a love of horror stories and wild imaginings. But Lana insists they are too old for pretending. It's time for a different game: serving Him, a figure she sees lurking in the dark, mysterious and demanding. According to Lana, she and Maddie must obey Him or else suffer the consequences. Maddie doesn't want to lose her most important friendship, even if it means luring an innocent girl into the woods--as a sacrifice for Him.

Ten years later, Maddie is released from an institution and must reintegrate into society for the first time as an adult. While finding her first job and forming new friendships, Maddie struggles to determine what it means to forgive--or to trust--herself. Particularly when she discovers an online community that is not only eerily obsessed with her but committed to the cult of Him.

This is Maddie's chance at absolution--to convince them not to follow in her violent footsteps. But the loyal devotees have a pull. And Maddie knows that these games often have deadly consequences.