In the first season of the series "My Girl," Major Grigory Leonov, a senior detective, serves at the St. Petersburg Main Directorate of the Ministry of Internal Affairs. He easily solves complex cases and fearlessly catches criminals with his own hands. But his life is divided into "before" and "after" due to the tragic death of his wife. This happens right before their ten-year-old daughter, Masha, who is watching. Grisha is forced not only to raise the girl alone but also to constantly take her with him to work: after the tragedy, Masha refuses to be separated from her father, even for a few minutes. Everything would be fine, but this weakness of the major's is soon noticed not only by his colleagues but also by criminals...