The hunter for rare books Dean Corso does not suffer from modesty and skillfully knows how to get rare and priceless publications, not always by honest methods.
As a result, he acquired a not very good reputation. A wealthy and influential customer, Boris Bolkan, contacts him and entrusts him with an important task. He needs to verify the authenticity of a recently purchased antique rare edition called The Ninth Gate to the Realm of Ghosts. Only three out of nine remained in the world, six others were burned. The collector believes that only one of the remaining three is genuine, the rest are fakes, and wants to prove it. This work promises a generous reward. The antiquarian agrees to do the job, tempted by a large fee, but runs into trouble that makes him regret the decision.
Corso begins his research with a visit to the previous owner of the relic, who recently took his own life. The widow of Mr. Telfer, Liana kindly received him in her house, but it was news to her that her husband had sold such a valuable specimen. As soon as Mrs. Telfer learns about how the late husband disposed of the property, she immediately decides to return the relic. She comes to the main character and tries to seduce him, persuading him to stage a robbery. For this, she promised twice the amount of the reward. When nothing comes out of her, she goes into a rage and attacks the adamant offender, breaking the bottle on his head. She does not find what she was looking for in the antiquary’s apartment, as the prudent young man took care of safety in advance by hiding the rarity in his friend’s bookstore. As soon as he comes to his senses, he goes to get a book, but finds his friend’s corpse hanging by the leg exactly as on one of the engravings of that same dilapidated volume. However, the robbers could not find the volume itself. Mr. Corso decides to refuse a dangerous task, but the customer is adamant and increases the amount of remuneration. Commercialism takes over, and he continues to work.
Mr. Corso goes to Europe, to other owners of copies, the authenticity of which has yet to be determined. While traveling by train, the hero meets a girl with green eyes named Irene Adler. It turned out that they were on their way to Portugal, where one of the owners of the Ninth Gate lives. The mysterious girl periodically came across the detective on the way, and he had the feeling that she was watching him. In Portugal, an examiner examines both volumes and finds several differences in the illustrations. Some have Lufitzer’s signature. He understands that these differences were not made in the process of copying, with the aim of creating a fake, but intentionally.
The main ones are:
- the elder’s keys now in one hand, now in the other;
- the martyr was hanged now by the right, then by the left leg;
- arch walls with and without brickwork;
- the number of towers in the castle is now 3, then 4;
- and others.
In these differences lies the main mystery of the Ninth Gate. The find is surprising, but the book detective’s life is in danger. On the tail is a pursuer who dares to attack. The green-eyed stranger arrives in time and saves him.
Corso informs the client about his discovery, for which he immediately receives the task to get the second volume. At this moment, Irene appears and offers to go to the owner of the second copy. When they arrived, they found the owner’s dead body, and that slowly smoldering in the fireplace. In an attempt to save him from the fire, they found that the pages with engravings had been torn out. Things are getting more dangerous. The mysterious companion never revealed herself, but continued to help in the investigation.
They went to Paris to Baroness Kessler, who has a third copy. The elderly lady does not immediately get along with the guest, and for the first time puts him out the door. But then he willingly agrees to help when he finds out that all three books are authentic and have differences. In the process of studying, the main character is again attacked right in the library of the baroness. When he came to, the woman was dead and the library was on fire. Miraculously, he is saved. When he returns to his room, he finds the last third original missing.
Dean realizes that the kidnapper is the widow Liana Telfer, who originally wanted to get the rarity back. Together with a mysterious stranger, they find her castle and try to get inside to get back the stolen goods. But they end up at a meeting of a sect, which suddenly is his employer Boris Bolkan himself. He kills the widow in front of the sectarians and the protagonist. Gathering together the stolen original pages with Lucifer’s signature, he casts a spell, proclaiming himself immortal. But the flame consumes him. The hero saves all nine engravings from the fire and leaves the castle. Iren explained the reason for the failure of Boris by a fake of one of the sheets, now the hero’s shoulders are the goal of finding the last original page.