Arthur Bach (Dudley Moore) is a spoiled alcoholic from New York City who likes to be driven in his chauffeured limousine through Central Park. He is heir to his father Stanford's (Thomas Barbour) $750 million fortune, which he is told will only be his if he marries the upper class Susan Johnson (Jill Eikenberry). He does not love Susan, but his family feels she will make him finally grow up. Arthur reluctantly agrees to the arranged marriage, but he meets a working-class Queens waitress, Linda Marolla (Liza Minnelli), and despite her being a shoplifter, is attracted to her.
Arthur struggles with his promise to marry Susan. While visiting his grandmother Martha (Geraldine Fitzgerald), Arthur shares his feelings for Linda, but is warned again that he will be disowned. His valet, Hobson (John Gielgud), who has been more like a father to him than Arthur's real father, realizes that Arthur is beginning to grow up and secretly encourages Linda to attend Arthur's engagement party, telling Linda he recognizes when a young man is in love. Hobson is hospitalized and Arthur rushes to his side. After several weeks, Hobson dies and then Arthur, who has been sober that whole time, goes on a drinking binge. On his wedding day, he visits the diner where Linda works and proposes to her. At the church, he jilts Susan, resulting in her abusive father, Burt Johnson (Stephen Elliott), attempting to stab Arthur with a cheese knife, though he is prevented by Martha.
Arthur tells those in the church that there will be no wedding and passes out. Linda attends to his wounds and they discuss living a life of poverty. A horrified Martha tells Arthur that he can have his fortune because no Bach has ever been working class. Arthur declines, but at the last minute, talks privately to Martha. When he returns to Linda's side, he tells her that he declined again – Martha's dinner invitation, he means, but he did take the money. Arthur's pleased chauffeur Bitterman (Ted Ross) drives the couple through Central Park.
Arthur is a 1981 comedy film written and directed by Steve Gordon. The film stars Dudley Moore as the eponymous Arthur Bach, a drunken New York City millionaire who is on the brink of an arranged marriage to a wealthy heiress, but ends up falling for a common working-class girl from Queens. It was the first and only film directed by Gordon, who died in 1982 of a heart attack at age 44.