For 34 years, a woman has been living in fear that her son is being brought up in someone else's family. She is sure that a child was substituted for her at the maternity hospital. The mother has the second blood type, the father has the first, and the son has the fourth, and this is impossible. The son does not believe in his substitution in the hospital, and the mother denies treason. Both have passed a genetic examination. What will be the truth 34 years after the birth of a woman in Orenburg?