A bum is run over by a car. Some guy in a business suit gives him CPR for some reason and save his life somehow. The suit then tells us about pain and that nothing has been right in his life since the summer of '58. He pulls some painting out of an envelope.
Now we're in 1958 when this guy, named David of course, was a kid. While at the river he runs into some older girl. They get along well. She tells him she lives with her aunt, Ruth, and sister, Susan, next door to him, after her parent died in a car accident.
This was a time when doors were kept unlocked and kids just showed up in your living room. We meet some of the other teen and preteen kids in the neighborhood, mostly mean guys who don't treat girls well. They also play mean games. David and the girl, Meg, run into each other a couple more times and they start liking each other, even though David seems several years younger. David starts visiting Meg at Ruth's place. There are always a bunch of kids there. Ruth is single, and for some reason she offers these kids beer and cigarettes. She gives moralizing speeches aimed to belittle Meg and Susan. Susan is disabled, wears knee braces, and uses crutches, but that doesn't stop Ruth from violently disciplining her in front of the kids.
One day Meg gives David a painting--the same painting from the intro. When Ruth finds out she interprets it as proof that Meg is a slut. After more abuse eventually Meg is bound in some torture position in the basement while Ruth and all the kids figure out how to make her suffer. They take her clothes off, start cutting her, burning her, eventually raping her. And things go downhill from there, while no one dares say a word and everyone except David participates enthusiastically.
And that's what this movie is about--human inhumanity and cruelty--for the sake of cruelty. It's never clear what Ruth gains from all this, what her motivation is. Perhaps it's just the sorry need to feel superior and doing something because it can be done. I guess that's the common denominator in all torture whether in the 50s or today, allegedly for the sake of "security." More than horror torture porn, this is rather drama torture porn, it's not particularly explicit or visually gruesome. The movie is fairly slow and oddly enough the filmmakers don't bother to establish the character of Meg enough, which is why we can't really feel for her all that much until the very end.