Well to-do Chicago resident Chester "Chet" Ripley (John Candy), his wife Connie (Stephanie Faracy), and their two sons 16-year-old Buck (Chris Young) and 12-year-old Ben (Ian Giatti) are on vacation at a lake resort in Pechoggin, Wisconsin. Chet is a fun-loving father and husband looking for a get away for his family. All is going as planned when four unexpected visitors show up with a video camera in hand at the lake resort lodge. The four unexpected visitors are Connie's outgoing sister Kate (Annette Bening), Kate's know-it-all investment broker husband Roman Craig (Dan Aykroyd), and Kate and Roman's 10-year-old twin daughters Mara (Rebecca Gordon) and Cara (Hilary Gordon) who arrive to suprise Chet and Connie, having decided not to vacation in Europe. Roman is a typical Mercedes-driving, investment focused, '80s yuppie, and he and Kate live in the posh Chicago suburb of Oak Park. Roman seems to take pleasure in making sure others are well aware of his wealth and (supposed) expertise on many subjects, while Chet both finds his brother-in-law annoying and intreging at the same time.