Fred Astaire plays song-and-dance man Tony Hunter, whose top-hat-and-tails brand of movie musical has become passé. As the movie opens, a Hollywood memorabilia auctioneer tries to sell off a hat and cane that once belonged to Hunter, but he literally can't get 50 cents for them. His star on the wane, his life at a crossroads, Tony travels to New York by train to take stock and ponder his future. When the train pulls into Grand Central Terminal, he thinks the gaggle of reporters on the platform is there to see him, but it turns out they were waiting for Ava Gardner, who was also on board. A deflated but amused Tony strolls off alone (song: "By Myself'').Tony's solitude is short-lived -- he receives a raucous welcome inside the station by two of his best friends, Lily and Lester Marton (Nanette Fabray, Oscar Levant), a Broadway show-writing couple. They want Tony to star in a brand-new stage musical they've just completed, and they know who they want to direct it: acclaimed actor-director Jeffery Cordova (Jack Buchanan), who currently has five shows running on Broadway, including Oedipus Rex, which he's starring in himself. Tony, who's never heard of Cordova, listens politely as they stroll along 42nd Street, which Tony barely recognizes after all these years. He sends the Martons ahead to dinner in a taxi so he can spend some quality time in an arcade (song: "A Shine on Your Shoes'').The Martons take Tony to Oedipus Rex, where they watch from the wings. Tony has trouble believing the star and director of such a serious work would want to do a musical. Tony meets Cordova, who's a little slow to recognize him but then expresses great excitement at the prospect of working with him. Tony asks Cordova if he's truly interested in producing a musical; Cordova insists all theatrical genres are valuable.The Martons pitch the idea of their light, frothy musical: Tony would play an author of children's books who feels he's compromised himself artistically by writing lurid yet lucrative murder mysteries on the side; Lily says his success makes him feel as though he's "sort of sold his soul to the Devil.'' Jeffrey seizes upon that phrase to offer his vision of what the musical should be: a modern retelling of Faust, with himself playing the Devil in the guise of a book publisher. Lily, Les and Tony are taken aback. Tony doesn't think it will be his kind of musical, but Jeffrey tells him the show will make him a star all over again. As for Tony's insistence that he's "just an entertainer,'' Jeffrey replies that they're all entertainers (song: "That's Entertainment!'' ).Cordova sets about lining up financial backers for the play. He also knows who he wants as the leading lady: a rising ballet star named Gabrielle Gerard (Cyd Charisse), even though it's well known that her mentor and boyfriend, Paul Byrd (James Mitchell), won't let her do a Broadway show. Cordova solves that problem by offering Paul the job of choreographing the musical, and finagling Paul into demanding that Gabrielle co-star, or he won't do it. Tony, who goes with the Martons to see Gabrielle perform, thinks she's fabulous but is apprehensive about starring opposite a classically trained -- and noticeably tall -- ballerina. As it turns out, Gabrielle is nervous about working with a Hollywood legend like Tony. Their initial meeting goes badly amid mutual misunderstandings, but by this time the investors are totally sold on the concept, and it's too late to back out.Work begins on the musical, to be called The Band Wagon. Tony feels out of his element, and worse, that he's being patronized by Jeffrey, Paul and Gabrielle. He finally storms out of rehearsal. Lily and Les are concerned about their friend, but end up getting into their own argument. with Les accusing Lily of being overly enthralled by Jeffrey. (The Martons continue to work on the show -- but refuse to talk directly to each other.)Tony throws a temper tantrum in his hotel room. Gabrielle shows up; Tony tries to apologize, but she lets slip that Paul ordered her to apologize to him. They start to bicker again. Gabrielle bursts into tears, saying she knows Tony never wanted her in the show, which a startled Tony denies; for his part, Tony confesses how scared he's been of this project.Setting aside their differences, Tony and Gabrielle decide to find out if they really can dance together. They go for an evening carriage ride in Central Park, chatting and getting to know each other better. Alighting from the carriage, they stroll past a party of dancing couples and reach a clearing where they're alone. And there, they find they can in fact dance together, beautifully (song: "Dancing in the Dark'').Frantic preparations begin for the show's tryout in New Haven, Connecticut. It's an incredibly complicated production, with a plethora of elaborate sets. When it comes time to rehearse the first act finale, it seems to go smoothly at first, but quickly degenerates into a farce with different parts of the set moving up and down in the wrong directions. The pyrotechics-laden damnation scene (song: "You and the Night and the Music'') fares little better.The much-anticipated New Haven premiere lays a huge egg (complete with onscreen visual metaphor). Tony shows up for the post-premiere party at a hotel ballroom, but none of the financial backers or other cast members is there. Tony finds the chorus holding a party/wake in one of their rooms, complete with pizza, beer, ham and deviled egg. They warmly greet Tony, who regales them with stories of his early show business career. They're soon joined by Gabrielle as well as Lily and Les, who've patched things up. Clowning around, Tony, Lily and Les perform a comical number (song: "I Love Louisa'') which cheers everyone up at first. But the mood turns somber over their failed production. Tony makes a decision. He tries calling Jeffrey to tell them they're going ahead with the show, only they're going to return to the Martons' original script and songs. The person on the other end turns out to be a cleaning woman, but it doesn't matter, because Jeffrey entered the room without anyone noticing and has overheard Tony's little speech. Jeffrey admits his approach was wrong, and asks to be a part of the revamped Band Wagon. Gabrielle also insists on staying with the show, even though Paul (who showed up with Jeffrey) demands she withdraw; she watches sadly as Paul walks out.With Tony effectively in charge, the show travels to Philadelphia, Boston, Washington, D.C., and Baltimore. Along the way, the company polishes a series of musical numbers (songs: "New Sun in the Sky,'' "I Guess I'll Have to Change My Plan,'' "Louisiana Hayride,'' "Triplets''). During the train ride from Washington to Baltimore, Tony confesses to Les in private that he's fallen in love with Gabrielle.Opening night on Broadway. It's raining as Tony and Gabrielle arrive at the theater and wish each other luck. Tony awkwardly tries to express his feelings for Gabrielle, but thinks the better of it. In addition to the other musical numbers, the show's pièce de résistance is a spoof of hard-boiled detective novels called "Girl Hunt'' in which Tony plays private eye Rod Riley; Gabrielle plays two roles, that of an anguished blonde ("scared as a turkey in November'') and a sinister brunette ("She came at me in sections. More curves than a scenic railway'').The Band Wagon proves a hit. Afterward, Tony, in his dressing room, is puzzled by how quiet things are after a successful opening, but tells his valet he's going out to a nightclub to celebrate, even if he's alone (reprise: "By Myself''). As he exits his dressing room, Tony is startled to find the entire company waiting for him onstage with a surprise party prepared in his honor. Everyone sings, "For He's a Jolly Good Fellow.'' Gabrielle, speaking for everyone, tells Tony what he means to them -- but she also conveys that she's now in love with Tony, having broken up with Paul. Gabrielle meaningfully concludes, "The show's going to run a long time. And as far as I'm concerned, it's going to run forever.'' An overjoyed Tony kisses Gabrielle. They then join Jeffrey, Lily, Les and the company for a reprise of "That's Entertainment!'' as the movie ends.