Dina lives for one purpose - to save her son Anatoly. The young man has a heart condition. Without an urgent operation, he will not live even a year. But this requires a lot of money.  Dina earns money wherever she can - she cleans the neighbors, washes the floors in the entrance. But suddenly a rich neighbor Tamara gives Dina the money she needs. Now Dina will be able to pay for the operation. However, Tamara is soon found dead, and Anatoly is arrested on suspicion of murder.  Dina needs to find the real culprit. But how to do this if her son himself admits guilt?