Aided in his quest for vengeance by his beautiful and silent assistant Vulnavia, Phibes uses the Ten Plagues of Egypt as his inspiration, wearing an amulet with Hebrew letters corresponding with each plague as he conducts the murders. After three doctors have been killed, Inspector Trout, a detective from Scotland Yard, learns that they all had worked under the direction of Dr Vesalius, who tells him the deceased had been on his team when treating Victoria, as were four other doctors and one nurse. Trout discovers one of Phibes' amulets (torn off during a struggle) at the murder scene of the fourth doctor, which takes place while he is interviewing Vesalius. He first takes it to the jeweller who made it, then to a rabbi to learn its meaning. Now believing Phibes may still be alive, Trout and Vesalius go to the Phibes mausoleum at Highgate Cemetery. Inside they find a box of ashes in Phibes' coffin, but Trout deduces they are probably the remains of Phibes' chauffeur. Victoria's coffin is empty.
