The Demon Deep in Oklahoma (1970)

Katie Heaton lives with her older brother, Wes, in their remote childhood home that sits in the middle of nowhere in a small town in Southeastern Oklahoma. Trapped inside the four walls full of bad memories and sadness, the two siblings do all they know how to preserve the peace and quiet, but brace themselves for what is inevitably to come. One day Tommy, an old friend visiting Wes, arrives for an overnight stay. Secrets come out, suspicion is raised, passion ignites and all hell breaks loose.