Overview
18 Again! is a 1988 American fantasy-comedy film directed by Paul Flaherty and starring George Burns and Charlie Schlatter. The plot involves a college student switching souls with his grandfather by means of an accident. The film is based on the song "I Wish I Was Eighteen Again" written by Sonny Throckmorton and recorded by Burns in 1980.
Plot
Jack Watson is a millionaire playboy and businessman who is about to turn 81 years old just as his grandson David is about to turn 18, but Jack laments his old age and wishes to get back to his teens once more. When an accident switches their souls, Jack gets to live his grandson's life and all that it entails: school, sports, and romance. Unfortunately, David gets the "short end of the deal", as not only is he trapped in his grandfather's 81-year-old body, but he is also in a coma. The only one who knows the truth is his longtime friend Charlie, whom Jack was able to convince by recounting experiences only they knew.
Jack gets to approach his family from a fresh point of view and doesn't always like what he sees: he's been a distant parent for his son Arnie and has repeatedly disregarded his ideas for improving the family company. The college fraternity that he coerced David into joining (his old alma mater) is bullying him on a regular basis and forcing him to write their test finals for them. He also finds out that his girlfriend Madeline is unfaithful when she tries to seduce him, thinking he's Jack's grandson. Deciding to set things right, Jack in David's body decides to take charge by convincing his father (or rather, Jack's son) to implement his ideas on the family business and uses his poker playing skills to beat the frat boys while betting $1000 that he will beat the lead frat boy Russ in the upcoming track meet. Jack also impresses a girl named Robin, who is taken with David's old-fashioned style with bow ties and his vividly recounting the Second World War and meeting President Harry S. Truman.
However, Jack realizes too late that he has willed half of everything to Madeline, who convinces Arnie and his wife to disconnect Jack's 81-year-old body from life support. Knowing that this will kill David, Jack and Charlie rush to the hospital to prevent this, wheeling Jack's body away from an orderly. When they crash in the hospital chapel, Jack and David's minds are returned to their rightful bodies, and Jack awakens.
From Wikipedia (CC BY-SA 4.0).