Jalmari, who does odd jobs at the harbor, rescues little Risto from being beaten up by older boys. The child is afraid of his violent foster parents and runs away to kind-hearted Jalmari. His foster mother Miina reports the escape to the Salvation Army, whose lieutenant Sirkka finds the boy in Jalmari's shabby cottage. Risto runs away again when they try to return him to his foster parents.

The new idealistic welfare officer Helmi tries to improve conditions in "Sin Alley," but difficulties arise, particularly with the leader of the petty criminals, Jukka, whose son Reino also drifts into a life of crime.

Two children get involved in the adventure as the bustling caretaker Mrs. Aaltoska and crime reporter "Hawkeye" Lipponen start chasing the mysterious criminal league.

Little Matti, who has been living in the countryside with his grandmother, leaves for Helsinki to search for his missing mother, Kerttu. In the city, he is helped by Taneli, a homeless alcoholic artist, and Salme, a girl who lives with her alcoholic aunt.

A story about the life of Eero, a machine shop worker, and his younger brother Martin in the working-class neighborhoods of Helsinki, and the change brought about by a conductor and his daughter who move in next door.

The story of Pekka Aalto, who lives with his aunt and to whom district judge Anders bequeaths a large estate. No one knows who this young Pekka Aalto is, and the whole truth will not be revealed until six months later in the supplementary will. Anders' sisters do everything they can to prevent Pekka from getting the estate promised to him in the will.

It is the summer of 1941. An eastern-Finnish machine gun company receives an order to turn in their surplus equipment. The company is transferred to the front lines. The next morning the soldiers wake to the sound of guns – the war has begun.