Pekka Puupää and Pätkä form a two-man orchestra, a quirky duo whose street performances blend stubborn charm with offbeat rhythm as they chase a break in show business. Before they even hit the road, they stumble upon a catchy tune in a music store display and learn the song Hippa ja Hoppaa, which they eagerly practice on crowded sidewalks, leaving passersby both amused and puzzled.
On tour through Turku and Tampere, their act rides the edge of boredom and indifference, with sparse crowds and a taste of frustration shadowing every note they play. In Pori, the audiences are so small that only a single sleeping spectator remains to witness their set, and the pair trudges back to Helsinki feeling more defeated than triumphant, yet not completely discouraged.
Back at home, life takes an unexpected turn as a summons for military refresher training lands on their doorstep. The two old friends are drawn into a frogman course, where the water becomes their new stage and the training tests their endurance as they push through rigorous swimming and diving drills. While practicing these techniques in the outer archipelago, they encounter something extraordinary: a mermaid, Helmi, whom they decide to bring along for the ride to add a dash of wonder to their routine.
Back on shore, they leave Helmi waiting in a bathtub, where Justiina Puupää finds her, mistaking the shimmering creature for a giant pike. The discovery sends ripples of astonishment through the home front, as the unlikely encounter blurs the line between ordinary life and seaside fantasy. Alarmed by the surreal sight, Justiina calls for Pikkarainen, the janitor, whose reaction mirrors the film’s mix of humor and astonishment.
As the mermaid’s presence unsettles the routine, she becomes a kind of water maiden, a whimsical fixture at Linnanmäki amusement park that adds color to the sailors’ and soldiers’ days and injects momentum into the story’s lighter moments. In the midst of it all, a boxing match between the navy and the army provides a lively backdrop, underscoring the blend of competition and camaraderie that threads the film together.
Eventually, the two are discharged with thanks, returning to everyday life with a sense of earned relief. Yet their calm is short-lived: while reading a newspaper on a park bench, two departing UN peacekeepers knock them unconscious and switch uniforms, setting in motion a far-flung misadventure that propels Pekka and Pätkä toward a global stage they never anticipated. They are then sent to Helsinki-Vantaa Airport, where a plane carries them to a Finnish UN peacekeeping camp in Suez, joining a journey that started with music and mischief and ends in an unlikely act of international duty.
