It's time for the annual Mayflower Dog Show and various canine owners and fanatics across the country are preparing for the big event and traveling to Philadelphia. Among them are yuppie Illinois lawyers
Meg (PARKER POSEY) and Hamilton Swan (MICHAEL HITCHCOCK), who are about as uptight as one could imagine, worrying both about the competition and the effects that their sex life has on Beatrice, their Weimaraner.
Then there's Gerry (EUGENE LEVY) and Cookie Fleck (CATHERINE O'HARA) from Fern City, Florida. Driving up the east coast with their Norwich Terrier, Winky, they encounter various past lovers of Cookie's, few of which Gerry was previously aware. From Pine Nut, North Carolina comes Harlan Pepper (CHRISTOPHER GUEST), a charming fly fishing shop owner, and his Bloodhound, Hubert.
Longtime New York gay couple Scott Donlan (JOHN MICHAEL HIGGINS) and Stefan Vanderhoof (MICHAEL McKEAN) have high hopes for their Shih Tzu, Agnes, that Scott has trained, while the wealthy, but elderly Leslie Cabot (PATRICK CRANSHAW) and his young trophy wife Sherri Ann (JENNIFER COOLIDGE) believe that their Standard Poodle, Rhapsody In Blue, will keep the reigning championship crown due to the efforts of their trainer, Christy Cummings (JANE LYNCH).
With everyone arriving in Philly where a hotel manager (ED BEGLEY, JR.) does everything in his power to accommodate them, Dr. Theodore W. Millbank III (BOB BALABAN) the earnest president of the Mayflower Kennel Club and the show's chairman, Graham Chissolm (DON LAKE), open the competition. As TV commentators Buck Laughlin (FRED WILLARD) and Trevor Beckwith (JIM PIDDOCK) call the event, the various contestants and their dogs do their best to win their individual categories and then compete for the big prize.