DI Rebus is back, investigating a fatal shooting at a private school north of Edinburgh.Two seventeen-year-olds are killed by an ex-Army loner who has gone off the rails. As Detective Inspector John Rebus puts it, 'there's no mystery...except the why'. But this question takes Rebus into the heart of a shattered community. Ex-Army himself, Rebus becomes fascinated by the killer, and finds he is not alone. Army investigators are on the scene, and won't be shaken off. The killer had friends and enemies to spare and left behind a legacy of secrets and lies.