Cass has a theory: everyone eventually leaves. Her father walked out, her mother is starting a new family, and she almost lost her best friend to cancer.

When Cass transfers to a preppy new private school, her plan is to stay anonymous by hiding her skater girl veneer beneath plaid skirts and knee socks. But when her cute locker neighbor, Cooper, takes an interest in Cass, keeping a safe distance isn't easy. And once Cass lets her guard down, the unthinkable happens: Cooper is mysteriously murdered.

As the investigation unfolds, Cass's close friend, Gav, is suspected as the killer. Determined to find answers, she must go through her list one by one until somebody cracks. However, will uncovering the truth really give Cass what she is looking for?