A backwoods game warden and a local doctor discover that giant leeches are responsible for disappearances and deaths in a local swamp, but the local police don't believe them.

In a racially mixed American town, a five-year-old black girl falls unnoticed into a hidden, forgotten well on her way to school. Having nothing better to go on, the police follow up a report that the child was seen with a white stranger, and rumors run wild. Before hapless, innocent Claude Packard is even found, popular hysteria has him tried and convicted. But is he guilty?