Senior Lieutenant Valery Samsonov is on the trail of a sophisticated, merciless killer, whose hands have already claimed two employees of a pharmaceutical company. Someone is methodically and cruelly murdering those connected to operation “Ultraviolet”—the development of a unique drug. But something went wrong with the scientists, and instead of the needed medication, they created a deadly weapon, the materials for which must by no means fall into someone else’s hands. Samsonov must prevent new victims at all costs, but the case is complicated by the fact that it is supervised by inconspicuous people from the secret services—the safety of the country is at stake…