Christine and Mike are an ordinary middle-class couple, living in what could be any house on any street. It's an average evening as they prepare dinner, open a bottle of wine and bicker as they wait for their teenage son Sebastian to come home from football. A ring at the door is answered by Christine. A terrible scream and she reappears, a knife at her throat, a gang of teenagers at her back, who tie them both up. It seems Sebastian has snitched on one of them and they are here to exact the worst revenge imaginable to a parent, but in the sincere belief they hold the moral high ground - that this is the right thing to do. They settle in to wait for Sebastian to come home.