The tranquil town of Pocatello, Idaho, is shaken when high school student Cassie Stoddart is discovered murdered in a secluded house. As the community grapples with the terrifying possibility of a random killer, authorities delve into Cassie's last day, zeroing in on three classmates who were the last to see her. As the inquiry progresses, detectives stumble upon a disturbing hidden videotape that alters the entire perspective of the case, leading to the harrowing consideration of whether teenagers as young as 16 could be capable of such a heinous act.