17-year-old tennis player Katya is forced to quit the sport. Her family has no money, no connections, and not even the desire to fight for her dream of the world of big-time sports. Now tennis has become a way of survival for the girl. Pretending to be a novice, Katya goes to private courts in Moscow and beats rich amateurs for money. One of these "duels" is witnessed by former professional athlete Igor Strelnikov, a tired coach who has long dreamed of finding a truly gifted child. When he sees Katya, he realizes that this is the "uncut diamond" and his chance to return to the world of big—time sports. Igor is making the biggest bet of his career on Katya.