Monsieur Brunel, a French detective on an exchange scheme in London, is assigned to investigate the murder of novelist John Morlar. As they examine the crime scene, Brunel discovers the victim is still alive in spite of his severe injuries and has him rushed to hospital.
With the help of Morlar's journals and Dr. Zonfeld, a psychiatrist Morlar was seeing, Brunel reconstructs Morlar's past life. Seen in flashback, it is filled with inexplicable catastrophes and the sudden deaths of people he disliked or who offended him. Morlar was even more convinced when a supposed psychic examined his hands, became ill, refunded Morlar's fee, and excused himself. Dr. Zonfeld scoffs at this explanation, asking Morlar if he seriously believes in palmistry as a means to predict the future.
As flashbacks continue, it becomes shown that Morlar is a psychic with powerful psychokinetic abilities. Disgusted at the world, Morlar has caused two recent disasters: an airliner crash into a London office tower and the loss of a manned spacecraft. Dr. Zonfeld, who came to see Morlar at his home, had tried to stop him from killing the astronauts in the spacecraft, but she had failed. She had then bashed in Morlar's skull with a blunt object.
Brunel eventually figures out that Zonfeld attempted to kill Morlar, and confronts her over it. She admits that it was her, but Brunel does not arrest her right away, as what evidence he has is not truly enough to prove, in a court of law, that she was responsible. Later, Brunel returns to Dr. Zonfeld's office, but he discovers her corpse where she had committed suicide, leaving a note where she admits the realization that she cannot live in a world in which Morlar also lives, apologizing to Brunel for leaving the mess for him to deal with. In the mean time, Brunel discovers that Morlar had mentioned, in one of his journals, news about a cathedral being built and how he intended to punish the hypocrisy of those praying there to God but caring nothing about the suffering He inflicts. From his hospital bed, Morlar manages to bring down the cathedral on the "unworthy heads" of a VIP congregation attending the fund raising event for the crumbling building's restoration. Morlar seems able to keep himself alive by sheer willpower. An enraged Brunel runs from the collapsing cathedral to the hospital, where he tries to kill Morlar to end the destruction, just as Zonfeld had tried to kill Morlar to stop him from killing the astronauts, but is also unsuccessful in stopping him. Morlar writes on a pad the name of his next target: the nuclear power station at Windscale (now Sellafield).
Who attempted to stop Morlar from killing the astronauts in space?
Dr. Zonfeld