No Book But the World — Leah Hager Cohen

At the edge of a woods, on the grounds of a defunct "free school,” Ava and her brother, Fred, shared a dreamy and seemingly idyllic childhood -- a world defined largely by their imaginations and each other's presence. Everyone is aware of Fred's oddness or vague impairment, but his parents' fierce disapproval of labels keeps him free of evaluation or intervention, and constantly at Ava's side.

Decades later, then, when Ava learns that her brother is being held in a county jail for a shocking crime, she is frantic to piece together what actually happened. A boy is dead. But could Fred really have done what he is accused of? As she is drawn deeper into the details of the crime, Ava becomes obsessed with learning the truth, convinced that she and she alone will be able to reach her brother and explain him -- and his innocence -- to the world.