Old Virtanen is a respected night watchman at a textile factory and a single father to his daughter Aino, who is about to graduate from high school. The heartless factory owner Kuusela fires Virtanen, who is forced to look for a new job. When Aino, who is in love with the manager's son Veikko, disappears after her graduation party, her father, who has fallen ill with worry, is overcome with despair.

In the 1880s, an unruly group of Cossacks stays in Sankola's house in Hämälä. Soon the group's leader Kuisma sets his sights on the house's adopted daughter Helina . Isma, the owner of the farm, has also fallen in love with Helina.

Sergeant Kalle Ryhmy, Second Lieutenant Ville Romppainen, and Mörökölli the cat travel from the front lines to Helsinki for a vacation. The trio, traveling by train, rescue the mysterious beauty Dora and Argentine war reporter Santa Rosa from a snowdrift, who lead them on the trail of an international spy ring hunting for military secrets.