Cassel (Johnny Depp) is obsessed with collecting bizarre and quirky rare books. This talent is greatly appreciated by the wealthy Balkan (Frank Langella). He gave Cassel the daunting task of finding an ancient book called The Ninth Gate and identifying the authenticity of the one in his possession. There are only three copies of this book in the world, and the remaining two have gone to Portugal and France.
Legend has it that by reading through this book, you can summon the coming of the devil. Cassel begins a tortuous and magical search. He visits the wife of the original owner of the book, an expert in the restoration of ancient books, and a mysterious woman with green eyes, during which his friend's violent death turns out to be exactly the same as the illustration in the book, and the murder is still being staged one after another. It turns out that the spells in the book may make no one who owns them spared. And if the three books come together, there will be an evil Satan. And in the end, did the devil's face appear?