When Julianne Hiller arrives at her best friend Piper Holden's house one late autumn morning, she discovers an eerie scene – the kettle is still warm, all the family’s phones are charging on the worktop, the cars are in the garage. But the house is deserted. In fifteen-year-old Riva Holden’s bedroom, scrawled across the mirror in blood, are three words: Make Them Stop What happens next?