It's June 4, 1968 and manager Paul Ebbers (WILLIAM H. MACY) is hoping to get his employees at Los Angeles' Ambassador Hotel ready for a late-night appearance by Democratic Presidential candidate Robert "Bobby" Kennedy following the California primary election. That is, when Paul isn't having an affair with Angela (HEATHER GRAHAM), one of his phone operators, much to the chagrin of her coworker Patricia (JOY BRYANT) and unknown to his hair stylist wife, Miriam (SHARON STONE), who also works in the hotel.
Yet, Paul has his hands full with other matters, such as disciplining his kitchen supervisor, Timmons (CHRISTIAN SLATER), who refused to let his staff -- including Mexican immigrants Jose Rojas (FREDDY RODRIGUEZ) and Miguel (JACOB VARGAS) -- have time off to vote. Black head chef Edward Robinson (LAURENCE FISHBURNE) tries to fill them in about how to operate in the white man's world, but Jose is nevertheless upset that he has to work a double-shift that night and thus miss attending a potentially historic baseball game with his dad.
Then there are the various weddings being held at the hotel that day, including between classmates Diane (LINDSAY LOHAN) and William Avary (ELIJAH WOOD). They're getting hitched only to keep him from being shipped off to Vietnam, something John Casey (ANTHONY HOPKINS) and his fellow senior citizen friend Nelson (HARRY BELAFONTE) no longer have to worry about. John's the former doorman at the hotel, and both he and Nelson hang out there since retirement has left them feeling lonely and a bit useless.
Kennedy's campaign manager Wade Buckley (JOSHUA JACKSON) feels anything but that, as his busy day is filled working with fellow idealist Dwayne (NICK CANNON) in all aspects of the big day, including dealing with Czech reporter Lenka (SVETLANA METKINA) who wants an interview with the candidate, as well as wrangling volunteers such as Cooper (BRIAN GERAGHTY) and Jimmy (SHIA LaBEOUF). While their intentions are good, they get sidetracked by philosophical hippie Fisher (ASHTON KUTCHER) who turns them on to LSD for the first time, a point that current waitress and aspiring actress Susan (MARY ELIZABETH WINSTEAD) finds endearing.
Speaking of performers, it's veteran entertainer Virginia Fallon's (DEMI MOORE) last night at the hotel, and she's drinking heavily as usual, behavior that doesn't sit well with her stage husband Tim (EMILIO ESTEVEZ). And speaking of husbands concerned about their wives, there's depressed East Coast socialite Jack Stevens (MARTIN SHEEN) who thinks his much younger missis, Samantha (HELEN HUNT), should be concerned with things that are more substantial then her looks and what shoes she's going to wear to the night's big political party, an event everyone is looking forward to.