The man named Lucifer saw himself as the arch-demon dwelling with loyal subjects in preparation for Armageddon. The criminal genius named Seff saw in him an uncanny psychic ability to predict a person's probability of death. Armed with this information, he came up with a bizarre extortion scheme. When Lucifer's abilities seemed to be slipping, it became imperative to find out why and that meant forcing the help of a Professor Collier, who happened to be a new friend of Modesty Blaise.