L prepares to say goodbye to the world when he suddenly gets a message from F, which then tells him about a mysterious virus that killed all the inhabitants of a village in Thailand. Before his death, L F sends his successor - a small Thai boy with outstanding mathematical abilities. At the same time at the center of research into infectious diseases are discovered the truth - used in the attack on the village virus mutates constantly and in practice there is no cure him. Responsible for the research scientist who tries to find the antidote, sends his daughter to L, together with the effects of tests and sample of the virus. Some time later is found murdered, and our detective becomes his killers next target.