Equation with the unknown

Olga Zvereva, a young promising accountant, is getting a job in a large construction company. An office in the center of Moscow, a sexual director and a personal coffee machine in your own office - what else can you dream about?
However, the joy of Olga did not last long. Every morning she begins to receive yellow envelopes. The sender of letters threatens her with troubles and claims to know her main secret.
It soon turns out that someone in the company is draining secret information to competitors, and Olga itself is suspected of this. Now, at all costs, it is necessary to calculate the one who blackmail it - maybe he just transfers data? In addition, Olga’s most terrible secret about her past is really ready to go outside