Pekka ja Pätkä salapoliiseina

At Justiina's insistence, Pekka and Pätkä are looking for work again and end up starting a detective agency. The first assignment takes the duo on a cruise on Lake Saimaa. Traveling on the same ship are representative Johannes Kulo and his daughter Maija, as well as the lumberjack Jussi, who gets caught up in the duo's misadventures.