If you haven't seen the movie, it helps to know at least a very little bit of the background. Basically the spirit of very ill Lily Tomlin has accidentally been transferred into the body of her straight-laced lawyer Steve Martin. She occasionally takes over his actions, but over the course of the movie they get to know one another intimately and slowly fall in love with one another. At the end, through plot development, with the help of a mystic (played by Richard Libertini) that spirit is finally transferred out of Martin and into the body of a beautiful woman (Victoria Tennant), where it can finally have free and complete reign. And at last, Martin and Tomlin have a chance to develop their romance.
Which brings us to the joyous end credits.