No one at the heart center suspects that nurse Leah Bran is a three-hundred-year-old vampire. She is smiling and good-natured towards people, tries to be a simple person and survive in the human world. Her friend Marian, a doctor at the same hospital, hides his secret - he is a human, but has been living for more than a hundred years. He and Leah have to find out the reason for their long existence, but for now they have another problem - strange deaths of employees occur at the center. Alain Dandeville is the elite of the hospital, the favorite of the authorities, a proud and arrogant cardiac surgeon. To find out who is killing his colleagues, he will have to take matters into his own hands. Suspicions fall on Marian, and then he comes face to face with Leah Bran, and Alain discovers the terrible truth about vampires and the legend called “Diablerie.”