1936 ... At night, doorbells are ringing more and more often in the apartments of Soviet citizens, and everyone knows that this does not bode well. Zinaida Krestovskaya, a single woman working as a pediatrician, also knows this. But such a night call, which scared her to death, did not mean what she had thought. On the doorstep stood the ex-fiancé, a psychiatrist, who literally begged to see a very strange patient. If Zinaida knew what her consent would turn into ... A mysterious patient without a name, registered under a number, carefully guarded by a secret NKVD unit, turns out to be ... a boy of ten or twelve ...
Zinaida Krestovskaya's more or less settled life is collapsing. She witnesses the terrible and ridiculous deaths of people who were somehow connected with a strange patient, a corpse is thrown into her room, and she herself is threatened ...