Dr. Heidegger invites to his study four elderly friends to engage in an experiment. Three are men: Mr. Medbourne, Colonel Killigrew, and Mr. Gascoigne; the fourth is a woman, the Widow Clara Wycherly.
The study is a dusty, old-fashioned room replete with a skeleton in the closet, a bust of Hippocrates, books and bookcases, and a portrait of Sylvia Ward, who died fifty-five years before the night of the experiment on the eve of marriage to the doctor after swallowing one of his prescriptions.
The doctor shows his guests a faded rose that she gave him those many years before, and places it in a vase containing liquid from the waters of the region in Florida where the Fountain of Youth is located, sent to him by a friend.
The rose revives and the doctor pours some of the liquid from the vase into four champagne glasses for his friends. They drink and shed their years, showing signs of intoxication. Dr. Heidegger suggests to them that they allow their experience in life to guide them in virtue and wisdom when they gain a second chance at youth. As they drink, their inhibitions vanish. Colonel Killigrew takes interest in the widow’s charms and flatters her; Mr. Gascoigne waxes eloquent in periods of a sort dear to politicians; Mr. Medbourne projects a plan to supply the East Indies with ice by means of whales harnessed to icebergs.
Dr. Heidegger does not take part in the rejuvenating experiment; he witnesses their antics with gravity. Young again, they laugh at their quaint clothes, showing contempt for the traits of old age that they have shed. Finally, the widow asks the doctor to dance with her, but he pleads old age and rheumatism. The three other guests seek to join her in dance, and in the ensuing riot, the table with the vase of the Water of Youth and rose overturns. The liquid reaches a dying butterfly, reviving it so that it flies to rest on Dr. Heidegger’s white hair. The rose fades; the guests show their age again. The doctor states that he is glad not to have partaken of the liquid; he has learned that this unnatural return to youth was no occasion for satisfaction. His guests, however, undaunted, determine to sally forth in search of the Fountain of Youth in order to drink from it three times a day.