Private detective Ignat Karataev is investigating the case of an attempt on the life of notary secretary Lera Kalinina. She once drew up a marriage contract for oligarch Arkady Sevryugin. And now, divorcing his wife, the rich man suddenly learns that, according to the agreement, he will completely lose his fortune. Did Lera accidentally make a mistake when drawing up an important document, or was she in cahoots with someone who wanted the businessman to ruin? Be that as it may, the girl was doomed to pay for what she had done with her blood. But the marriage contract turned out to be just a prelude to a terrible scam, and a seemingly simple criminal case suddenly appeared in a completely different light...