The Stooges operate a local drug store whose landlord, the cantankerous Amos Flint (Emil Sitka), informs them their lease is about to expire. Larry protests that the trio have had their establishment for a decade, and do not want to leave. As the four bicker, Flint's elderly wife Cerina (Christine McIntyre) enters the store, only to be berated by Flint for being an old hag. "25 years is enough," he coldly confirms. After he storms off, the boys take to the frail Cerina, who begins to weep that ever since she lost her beauty, Amos had threatened to leave. Both saddened and incensed, the Stooges offer Cerina their spare room in the back. Shemp, seeing this, hatches a plan to invent a "Fountain of Youth" to restore Cerina to her stunning beauty. Deeming the idea "tremendous, colossal and putrid," the Stooges flee to their pharmaceutical lab and mix together a powerful serum.
After several false tries, the trio give Cerina a taste of their Fountain of Youth, and she transforms into a fetching beauty right before their eyes. Several days later, Amos comes storming into the Stooges' drug store only to see the youthful Cerina flaunting her newfound beauty. Amos quickly reneges on his threat to evict the Stooges, and requests a dose of the youthful serum himself. The Stooges proceed to mix a new batch on the spot, resulting in Amos becoming a 5-year-old boy.
The following day, Cerina celebrates her return to youth by preparing a Marshmallow Jumbo layer cake. Shemp is assigned to hunt down some of the sweet confection, but inadvertently retrieves bubblegum. The resulting celebration then finds the Stooges and Cerina blowing bubbles after every bite, with Shemp getting two bubbles out of his ears.