The TV series "The Hat" tells the story of an unusual side job of a doctor-anesthesiologist. Ivan holds a position in one of the Moscow clinics, where he helps patients recover after injuries and surgeries. However, his salary is not enough to meet all the demands of the young doctor. Therefore, in his free time, he takes on private clients. Ivan works as an underground "hat" - he installs detoxification systems for famous singers, actors, and politicians who have gone overboard with alcohol or drugs. Of course, it doesn't come without its share of adventures.