Have you seen Carolyn Harper? That’s the horrid question that thumps in the hearts of the characters in the trippy teen-noir Knives and Skin. It was another quiet night in a Midwest small town when band geek Carolyn Harper went missing. Her pom-pommed shako cap will be found near a river that keeps silent on the secret of that night. But as her friends and family search for clues — or her corpse — the fragile façade of normalcy and pleasantry is shattered. In its place come boundary-pushing flirtations, uncomfortable parent-child confrontations, a mounting dread of mortality, and a string of acapella musical numbers, thoughtfully plucked from a catalog of ’80s classics.