A film centered around a popular Finnish song book. Young lovers Pirkko and Pekka break off their engagement at the end of an evening spent at a dance restaurant. At home, Pirkko finds a songbook in her room, whose songs turn into musical scenes. The night watchman carries the songbook with him, and it ends up, via a sad prostitute, a police officer, and a night shelter resident, with Pekka, who is waiting for Pirkko's forgiveness and comes to pick up his fiancée.

Three sailors rescue Carmen, who has fallen into the clutches of the white slave trade, and also manage to destroy a drug gang.

Pekka and Pätkä work as inventors. Pätkä accidentally takes a photograph of bank robbers, who begin to track down the photographer. Soma Koivu, the former secretary of the property manager Kiivas, and police officer Antero Kangas help Pekka and Pätkä catch the robbers at a film studio where Pekka is working as a stand-in for Superman.