As of November 1, 1959, mild mannered C.C. Baxter has been working at Consolidated Life, an insurance company, for close to four years, and is one of close to thirty-two thousand employees located in their Manhattan head office. To distinguish himself from all the other lowly cogs in the company in the hopes of moving up the corporate ladder, he often works late, but only because he can't get into his apartment, located off of Central Park West, since he has provided it to a handful of company executives - Mssrs. Dobisch, Kirkeby, Vanderhoff and Eichelberger - on a rotating basis for their extramarital liaisons in return for a good word to the personnel director, Jeff D. Sheldrake. When Baxter is called into Sheldrake's office for the first time, he learns that it isn't just to be promoted as he expects, but also to add married Sheldrake to the list to who he will lend his apartment. What Baxter is unaware of is that Sheldrake's mistress is Fran Kubelik, an elevator girl in the building who Baxter himself fancies. In turn, Sheldrake has no idea of Baxter's own interest in Fran. And Fran, who is in love with Sheldrake, has no idea that she is only the latest in a long line of Sheldrake's mistresses, that Sheldrake has no intention of leaving his wife for her, and that the apartment belongs to Baxter, who she likes as a friend. As some of these facts come to light on Christmas Eve, one of the three makes a unilateral decision. That decision sets off a series of events over the course of the next week which makes each of the three examine what he/she really wants which in turn may be incompatible with the other two. They are helped along the way by Dobisch, Kirkeby, Vanderhoff and Eichelberger who are now feeling neglected as Baxter no longer needs their assistance in moving up, by Miss Olsen, Sheldrake's long serving secretary who was also once his mistress, and by Dr. Dreyfus, a physician and one of Baxter's many exasperated neighbors who believes Baxter is a playboy based on all the noise he hears in Baxter's apartment and the plethora of empty liquor bottles Baxter seems to be always discarding.