The year is 1955, and these siblings are bound by more than blood. Their parents' strict rules have only fueled their forbidden fantasies. One evening, alone in the house, they succumb to temptation. She straddles him, his hands gripping her ass as she grinds against his erection. He teases her nipples, making her gasp. They're lost in each other, their bodies moving in sync, when a floorboard creaks, and they freeze, their secret almost discovered.