Eager young radio reporter Teräsvuori stages a one-man burglary into the Helsinki Art Museum, recorded on tape for a later broadcast by his friend Laakso. Things go awry when a gang of real criminals overhear their plans and book their heist to coincide. Teräsvuori gets caught but escapes from police custody to start his private investigations together with female radio colleague Eila.
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.
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.
