Set in turn of the century Helsinki, author Arvo Helavalla's novel makes an indelible impression on adolescent Auli Ranta. She idolizes the author of a work that can never be forgotten.
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.
Liisa and the renowned composer Raimo Kaarna are fond of each other, but in Kaarna's family history, everyone does not accept the relationship. In addition, Liisa has her own doubts, and a secret that does not endure the daylight.
