On a college campus, young men are dying of heart attacks. According to witnesses, they are last seen with young women who apparently died shortly before meeting the men. When Kolchak investigates, he finds that the men were associated with Professor Spate, who is researching an ancient Middle East tablet, and that a series of similar deaths plagued his expedition to recover the tablet. The tablet is tied to a supernatural creature known as a succubus, who possesses young women at the moment of their death and then reveals her true visage to men, frightening them to death and feeding upon their energies. Kolchak must destroy the tablet to destroy the succubus once and for all.