One day, doctors Speransky and Nikulin made an outstanding scientific discovery: they discovered the bacillus of indifference and ignorance. To describe its action, one of them selflessly instills it in himself.

Woven around the daily lives of two children, nine-year-old Nastenka and five-year-old Katia, this is a story of the 17 months' siege of Leningrad and of the people and families shattered by the war, their homes bombed and destroyed, their lives in a constant anticipation of the advancing German army and air raids.