Three girls were best friends - until friendship became murder...From the bestselling author of SUNBURN and LADY IN THE LAKEBaltimore police receive an urgent call out to a school after gunshots are heard coming from a locked girls' toilet.The police find three victims, but only Josie is conscious, and she insists she is not the shooter.Perri is unconscious from a bullet wound that has ripped through her jaw; and Kat is dead, shot in the chest.Detective Lenhardt soon uncovers information that is at odds with the story Josie is telling.Other clues at the scene suggest there was a fourth girl who witnessed the entire episode from behind a locked stall.Where is she now? How did she get out?The crime seems to reach back five years before this fatal shooting, when three girls met aged ten, and took a vow of eternal friendship.How did that passionate friendship change, evolve - and finally fall apart?