October 1987, Midland, Texas. Cissy McClure is looking after some children at her sister's house. While she is inside, her own 18-month-old daughter Jessica wanders around the backyard, climbs over a stone and falls into an abandoned well. The police and fire services are soon on the scene. A simple job of rescue, it seems - but, as day drags into night and one rescue attempt after another fails, tension reaches fever pitch.