During the celebration of the dean's anniversary, mathematician Olga Barkovskaya finds the culprit of the celebration murdered. Next to the body is a card from an unknown game, very similar to the one that was thrown to Olga the day before. It seems that Barkovskaya is being invited again to solve a mathematical puzzle, and a human life is at stake.
| Actor | Role |
|---|---|
 Alyona KolominaОльга Барковская | Ольга Барковская |
 Dmitriy PchelaГеоргий Иванов | Георгий Иванов |
 Elena ValyushkinaСветлана Васильевна Карташова | Светлана Васильевна Карташова |
 Наташа ВасильеваКира | Кира |
| ККристина ПономареваНина | Нина |