Justiina Puupää Siiri Angerkoski travels to visit relatives and leaves her husband Pekka Puupää Esa Pakarinen to manage the home in Helsinki. Pekka and his best friend Pätkä Masa Niemi immediately start dreaming up ways to earn money, since Justiina has not left any cash but has stocked up the groceries. In the opening days, they sell the food door to door, and with their earnings they place an ambitious advertisement in the newspaper for “Pekka Puupää's kindergarten.” At the same time, a petty criminal named Petteri Åke Lindman steals a millionaire’s baby, and he bolts in a taxi. The taxi driver, Erkki Saarikivi Tapio Rautavaara, is unaware of what’s happening and continues driving as Petteri runs.
Petteri hides the baby in Pekka and Pätkä’s apartment building, while Saarikivi tails the fleeing suspect. Petteri knocks the taxi driver unconscious and hides him in the apartment next door, creating a tangle of misunderstandings that Pekka and Pätkä stumble into when they return home and discover a baby in their care. The moment also catches the attention of their neighbor Ritva Ranta Tuija Halonen, who is horrified to find an unconscious Saarikivi in her own apartment. After they clear up the confusion, Ritva and Erkki end up on a date, adding a spark to the chaotic day.
The would‑be babysitters’ childcare methods are eccentric and ill‑informed. They feed the baby läskisoosi and rock the infant to sleep in a ceiling lamp, a sight that horrifies Ritva and prompts her to step in and teach them about proper childcare. Despite Ritva’s guidance, Pekka and Pätkä’s Pekka Puupää’s Kindergarten fails to attract customers, forcing them to pivot to a new money‑making idea.
A new plan takes shape when they agree to join a boxing match against the strong, famous Hermanni Ronski Uljas Kandolin. A mix‑up leads to Pätkä entering the ring instead of Pekka. Pätkä struggles in the bout until Ronski takes a sip from Pätkä’s camphor bottle—unbeknownst to them, the bottle is filled with a sleeping potion due to the messy state of Pekka’s medicine cabinet—and collapses into slumber in the middle of the match. Meanwhile, the baby has again been left outside to sleep in the carriage, and Petteri, who happens to be nearby, steals it once more. The thief is soon caught in the same taxi driven by Saarikivi, who recognizes him and takes him to the police station.
Justiina Puupää returns home and, upon seeing the uproar, prepares to punish her husband. Saarikivi, however, clears up the confusion after learning at the police station that Pekka and Pätkä were in the care of the millionaire’s kidnapped child. In a grateful turn, the millionaire Arvo Lehesmaa rewards Pekka and Pätkä handsomely for their unexpected assistance in reuniting him with his child. The film offers a playful portrait of a pair of well‑meaning but bumbling men who stumble into a series of comic crises, and in the end, their good intentions—and a bit of luck—bring about a light, cheerful conclusion.
