Although Czech republic is country free of rabbies, some cases of infected animals appear near one of villages in Sumava region. Virologist Pavel Rogl, that is in his thirties, has task to inspect the situation, supervise the vaccination and find the source of infection. He is also charged to elaborate an expertise for team of police detectives, that are investigating mysterious double homicide. It is possible, that murders are connected to infection. Is it a human murderer, or big beast that escaped?