Loyalties - Delphine de Vigan

Thirteen-year-old Théo and his friend Mathis have a secret. Their teacher, Hélne, suspects something is not right with Théo and becomes obsessed with rescuing him, casting aside her professionalism to the point of no return. Cécile, mother of Mathis, discovers something horrifying on her husband's computer that makes her question whether she has ever truly known him. Respectable facades are peeled away as the four stories wind tighter and tighter together, pulling into a lean and darkly gripping novel of loneliness, lies and loyalties.