Maxwell Smart, acting as a protocol officer since CONTROL was disbanded in the early 1970s, is reactivated as a counterintelligence agent by Commander Drury, of the United States Intelligence Agency.

Its first scheme involves turning a forgotten American scientist and using his weather control machine to extort US$250 billion from the United States Government.

Along with Drury's bumbling aide, Beamish, Smart recruits Larrabee, who, believing that he was under orders from Richard Nixon to stay at his post until relieved, has been living in his office in the now-abandoned CONTROL headquarters tending his office plants, Agent 13, Hymie the Robot (now employed as a crash test dummy) and ultimately, his wife, 99, to find the security leak that allowed the scientist to defect, locate the weather machine and disarm it.

They are opposed by a KAOS mole (John de Lancie) within the USIA, who is able to predict Max's every move with the aid of stolen copies of 99's unpublished memoirs.

The relative success of the film prompted the development of a short-lived (only seven episodes) 1995 weekly series on Fox, also titled Get Smart, with Don Adams and Barbara Feldon reprising their characters, alongside Andy Dick and Elaine Hendrix in the main roles.