During the Balkan Wars, General Nikolas Pherides visits the island of his wife's grave, accompanied by an American journalist named Oliver Davis. Upon arrival, they discover a household of people trapped there under quarantine due to a deadly plague. Among the stranded individuals are the house owner Albrecht, his ill wife, and Thea, a young nurse caring for them. As tensions rise, Dr. Drossos desperately tries to contain the spread of the disease while the inhabitants grow more fearful and superstitious.

Soon, a superstitious woman named Madame Kyra begins to influence the group, suggesting that a malevolent force, known as the vorvolaka, is responsible for the deaths. General Pherides, initially dismissive of such notions, gradually becomes convinced of a supernatural presence. Paranoia spreads among the quarantined as they struggle with despair and mistrust. The foreboding atmosphere intensifies as individuals' suspicions and dread threaten to tear apart their fragile coexistence.