A passenger plane crashes at Sheremetyevo-2 airport. Investigator of the Prosecutor General's Office Alexander Turetsky is trying to understand the circumstances of this disaster. Under the wreckage of the Tu-154, a container with a dangerous virus was found that could cause a total epidemic of a deadly disease in the shortest possible time. What is it: criminal negligence, fatal coincidence or malicious intent? Working through different versions, Turetsky comes to the conclusion that the mysterious disappearance of the outstanding biologist Nikolai Batkin on the eve of his trip to Sweden to receive the Nobel Prize is directly related to this tragedy.