After several unsuccessful attempts to get another job (mostly because he's overqualified), Brantley ends up working in the mailroom of Pemrose Incorporated, which is directed by his uncle, Howard Prescott (Richard Jordan). Pemrose was founded by Prescott's father-in-law; Howard received presidency of the company by marrying his boss's daughter, Vera Pemrose (Margaret Whitton).
Upon inspecting company reports, Brantley realizes that Prescott and most of his fellow "suits" (executives) are making ineffective and/or non-beneficial decisions. After Brantley notices an empty office in the building, due to one of Howard's frequent firings, he assumes the identity of Carlton Whitfield, a new executive.
While handling two jobs (switch between casual wear and business suits by stripping in the elevator), Brantley also falls head-over-heels for Christy Wills (Helen Slater), a fellow financial wizard who recently graduated from Harvard. At the same time, his Aunt Vera keeps hitting on him since they're not related by blood (Brantley's mother's cousin, before she was bit by a dog and died, was married to Howard Prescott's half-sister's nephew.)
Prescott, without Brantley's knowledge, is having an affair with Christy. When Howard asks her to spy on Carlton Whitfield, Christy falls head-over-heels for Carlton, not knowing he is actually Brantley. The Pemrose Corporation is preparing to merge with the infamous Davenport Corporation. Prescott, unaware that Whitfield and Brantley are one and the same person, suspects Carlton is a spy for uber-liquidator Donald Davenport (Fred Gwynne).
In the end, Brantley and Vera raise enough cash,...