A mistake of experiment may transform human into devil species. Dr. Diana and her father, Dr. Rung, discovered a new kind of snake-bite serum, X5N-1, was the great serum that could protect humans from snake poison. Both scientists were invited by World Health Organization (WHO) to receive a great award at Switzerland. Dr. Diana had to travel with Alex, her boyfriend, because her father would like to continue experimenting at the laboratory. During the experiment, Dr. Rung was bitten by a fierce snake. This made him transform into devil species with human's body and snake's head. At the same night, he killed all scientists in the research institute.