The dead river ()

When a Developer comes to a small town looking at a specific piece of land the locals try to warn him off because that particular piece of land is known to them as The Dead River. They tell the story of the Bates Family who in 1852 were cut off from society by the Great Flood. With this the family became incestious from lack of socialization and even cannibalistic. Well the Developer doesn't believe the locals and decides to survey the land anyways and finds himself in a world of trouble.