The last house on the left

Emma, John, and Mari Collingwood head out on vacation to their summer lake house. Shortly after arriving, Mari borrows the family car and drives into town to spend time with her friend Paige. While Paige is working the cash register at a local store, she and Mari meet Justin, a teenager passing through the town. Justin invites them both back to his hotel room to smoke some weed. After kidnapping and ruthlessly assaulting the two girls, Justin's father and his gang unknowingly find shelter from a storm at the home of Mari's parents, two ordinary people who will go to increasingly gruesome extremes to get revenge.