To get to know his girlfriend's son, a man volunteers to pick him up from a prep school... only to learn that her son's not the nicest kid.

It's vacation time for outdoorsy Chicago man Chet Ripley, along with his wife, Connie, and their two kids, Buck and Ben. But a serene weekend of fishing at a Wisconsin lakeside cabin gets crashed by Connie's obnoxious brother-in-law, Roman Craig, his wife, Kate, and the couple's two daughters. As the excursion wears on, the Ripleys find themselves at odds with the stuffy Craig family.

Buck Russell, a lovable but slovenly bachelor, suddenly becomes the temporary caretaker of his nephew and nieces after a family emergency. His freewheeling attitude soon causes tension with his older niece Tia, loyal girlfriend Chanice, and just about everyone else who crosses his path.