A former German officer is coming back to USSR in order to help to clear land mines he put during the war.
Siege of Leningrad, 1942. Despaired Nina Voronova evacuates from the city, leaving her little son along in a deadly cold apartment. He is found by Katya, a teenage girl from next door. She claims he’s her brother, and manages to get extra food provision from the district administration. When Alexey Voronov arrives to the city, he realises this little boy is his son.
