Charlie Bucktin, a bookish thirteen year old, is startled one summer night by an urgent knock on his bedroom window. His visitor is Jasper Jones, an outcast in their small mining town, and he has come to ask for Charlie's help. Terribly afraid but desperate to impress, Charlie follows him into the night.

Jasper takes him to his secret glade, where Charlie witnesses Jasper's horrible discovery. With his secret like a brick in his belly, Charlie is pushed and pulled by a town closing in on itself in fear and suspicion. He locks horns with his tempestuous mother, falls nervously in love, and battles to keep a lid on his zealous best friend. In the simmering summer where everything changes, Charlie learns why the truth of things is so hard to know, and even harder to hold in his heart.