Porter Stoddard (WARREN BEATTY) is a successful Manhattan architect who's just had an affair with Alex (NASTASSJA KINSKI), a beautiful cellist. While he's successful at hiding that from Ellie (DIANE KEATON), his wife of twenty-five years, his best friend, Griffin (GARRY SHANDLING), isn't as good at keeping his trysts secret from his wife, Mona (GOLDIE HAWN), who's recently followed him and discovered his affair.
While she doesn't realize that his lover was actually a man, Mona proceeds with divorce arrangements with lawyer David "The Shark" Suttler (BUCK HENRY). Meanwhile, Porter tries to maintain his normal family routine - which is anything but - with his young adult kids, Tom (JOSH HARTNETT) and Alice (TRICIA VESSEY), their respective others, Holly (KATHERINE TOWNE) and Omar (MARC CASABANI), and his housekeeper, Yolanda (TERRI HOYOS) and her shirtless, jungle lover, Alejandro (DEL ZAMORA).
Deciding to help his longtime friend, Porter flies to Mississippi with Mona to one of her homes where they end up in bed together. When they return, they agree to act as if nothing happened, but Ellie has gotten wind of Porter's infidelities - with the cellist - and he soon joins his friend in the proverbial doghouse.
The two men then decide to get away from it all by vacationing in Griffin's cabin in Sun Valley, a ski resort where they meet Auburn (JENNA ELFMAN), a hardware store clerk who take them to a Halloween party, and Eugenie (ANDIE MacDOWELL), a pretty but ultimately strange woman whose wealthy parents (CHARLTON HESTON & MARIAN SELDES) are even more bizarre than her.
As Griffin tries to get up the courage to announce that he's gay, and Porter deals with the various women in his life, the two try to figure out what to do with their lives, all while their wives do the same.