The horror film “Clown in a Cornfield” has a title that certainly delivers on its promise to ticket buyers: Yes, there is scary clown action in a cornfield. But as fans of Adam Cesare’s hit 2020 YA novel know, there’s plenty of twists below the surface we won’t spoil here — and many tell deeper truths about the heartland.

The initial plot concerns sullen teen Quinn (Katie Douglas) and her fraying bond with her depressed father (Aaron Abrams), who move to a sleepy Midwest town that is decaying after the local corn syrup factory shudders and is burned down. After falling in with a group of troublemaking teens, a clown that resembles Frendo, the factory’s mascot, begins terrorizing the town and targeting Quinn and her buddies. Yet near the midpoint of the movie, there’s a scene that plays against horror movie tropes so effectively that it acts...