Derek and Casey are back and continue their hilarious sibling rivalry during a family vacation to visit their grandmother at her beautiful lake front lodge. Things heat up with Casey when she meets Jesse, a handsome young dancer who is a waiter at the lodge. Meanwhile as Derek is chilling on his vacation, he falls for Roxy, the rich girl who lives across the lake. But when Roxys father, a greedy land developer, threatens to destroy the natural beauty around them, the McDonald-Venturi kids band together to save the lake and the lodge.