Stephanie and Terry are identical twins who have been raised separately since their parents divorced seven years earlier. Each envies the lifestyle of the other; and they decide, without telling Jeff or Mary, to switch families for a day or two. They soon find that it is harder to do what the other person is expected to do, and that looking alike is not enough. When they find that their charade may bring their parents back together, they agree to continue it. A major complication begins when Alice, Jeff's girlfriend and co-worker, finds out the real story.