Wink Poppy Midnight book by April Genevieve Tucholke

Every story needs a hero.
Every story needs a villain.
Every story needs a secret.

Wink is the odd, mysterious neighbor girl, wild red hair and freckles. Poppy is the blond bully and the beautiful, manipulative high school queen bee. Midnight is the sweet, uncertain boy caught between them. Wink. Poppy. Midnight. Two girls. One boy. Three voices that burst onto the page in short, sharp, bewitching chapters, and spiral swiftly and inexorably toward something terrible or tricky or tremendous.

What really happened?
Someone knows.
Someone is lying.