Fifteen-year-old Marina is given a terrible diagnosis - leukemia. Parents are shocked and they decide that only abroad can heal their child. But the oncologist Olga Nikolaevna convinces them that the girl cannot be taken away, but must be treated here, at home. In addition to everything, Marina has a rare blood group, which doctors do not have reserves of. The girl?s mother also cannot become a donor - she is expecting a second child, and an operation must be urgently needed ...