
The Path leads Langdon to four locations in Rome, each associated with one of the primordial elements: 'Earth', 'Air', 'Fire', and 'Water'. Langdon sets off on the Path of Illumination in hopes of delivering the Preferiti and recovering the antimatter canister. The clues indicate the secret meeting place of the Illuminati. Langdon attempts to retrace the steps of the "Path of Illumination", a process once used by the Illuminati as a means of inducting new members aspirants to the order were required to follow a series of subtle clues left in various landmarks in and around Rome. Their search is assisted by Camerlengo Carlo Ventresca (the late pope's closest aide) and the Vatican's Swiss Guard. Langdon and Vittoria search for the Preferiti in hopes that they will also find the antimatter canister. It is discovered that the four Preferiti, cardinals who are the most likely papal successor, are missing. Langdon and Vittoria make their way to Vatican City, where the Pope has recently died. The canister is somewhere in Vatican City, with a security camera in front of it, as its digital clock counts down to the explosion. When at CERN the canister is stored in a unique electrical charger which ensures the anti-matters stability but when removed its back-up battery provides power for 24 hours after which the anti-matter will self-destruct. Kohler calls Vetra's adopted daughter Vittoria Vetra to the scene, and it is ascertained that the Illuminati have stolen a canister containing antimatter - a substance with destructive potential comparable to a small nuclear weapon. Kohler contacts Robert Langdon, an expert on the Illuminati, who determines that the ambigram is authentic.

His chest is branded with an ambigram of the word "Illuminati". The plot follows Harvard symbologist Robert Langdon, as he tries to stop the Illuminati, a legendary secret society, from destroying Vatican City with the newly discovered power of antimatter.ĬERN director Maximilian Kohler discovers one of the facility's physicists, Leonardo Vetra, murdered.

The "Illuminati Diamond" mentioned in the book is an ambigram of the four elements arranged in the shape of a diamond.

The book also contains ambigrams of the words Earth, Air, Fire, and Water, which has served to bring the art of ambigrams to public attention by virtue of the popularity of the book. Besides the "Angels And Demons" and "Illuminati" designs, the title of the book is also presented as an ambigram on the hardcover book jacket (see illustration at right on this page), and on the inside cover of the paperback versions.

The book contains several ambigrams created by real-life typographer John Langdon.
