Hillary Kramer (Streisand), a successful perfume magnate awakes one morning to find that her accountant has robbed her blind and left for South America. Going through all of her remaining assets she finds a boxer, purchased as a tax write off. She decides to take Eddie "Kid Natural" Scanlong (Ryan O'Neal) who is much more at home giving driving lessons, into the ring and use him as her key to riches. Eddie thinks this will only get him killed and resists.
Eventually, Hillary wears Eddie down and she gets funding (mainly from friends, associates, and colleagues) for his first fights, all of which go awry, either through Hillary's lack of knowledge about boxing or Eddie's out-of-shape condition (and general fear of being hit). All the while, Hillary and Eddie continue sparring on their own, thanks to their different personalities. But, as time (and fights) go on, they develop an increasingly personal relationship, which ultimately leads them to have to decide what they really want.