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.
Esa Pakarinen
as Pekka Puupää
Masa Niemi
as Pätkä
Anja Hatakka
as Maija Kulo
Ami Lovén
as Jussi Leino
Siiri Angerkoski
as Justiina Puupää
Veikko Linna
as Johannes Kulo
Eino Kaipainen
as Leino (uncredited)
Juhani Kumpulainen
as Viljo Leino (uncredited)
Tauno Söder
as Rainer Strand (uncredited)
Armas Jokio
as Pikkarainen (uncredited)
Lasse Saxelin
as Lasse (uncredited)
Raimo Lehto
as Tolvanen (uncredited)
