Honey, We're Young at Heart

He's invented a machine that will make old people feel and act younger. However, it takes Diane and Wayne's youth, giving it to an older couple; the effects take a long time to kick in. As the other couple grows young and immature, Wayne and Diane grow old and scared for their lives. Can Nick and Amy find the old couple and bring them back before Wayne dies of old age and can't reverse the process?