Polanski returns to a satanic storyline with this adaptation of a Spanish novel. Depp plays a bespectacled, odious books specialist hired by a demonologist to authenticate his copy of The Nine Gates of the Kingdom of the Shadows, a tome purported to reveal a secret portal to the Underworld. Corso sets off to compare this copy with others already authenticated. Soon people are dying and copies are going missing as the whole investigation spirals towards a climactic encounter.