The colonel's wife's tin pints need to be cleaned up, and Sergeant First Class Körmy tasks two privates to do so.
Sergeant Friman is developing an automatic submarine detector that piques the interest of both, Swedish and Russian spies.
Relations between Sweden and Finland come to near breaking point. When further negotiations led by President Mara fail, Sergeant Körmy interferes in the course of events.
Lehmän vuosi