The story begins with the death of Leonardo Vetra, a scientist who has been conducting experiments with antimatter at CERN, the European Organization for Nuclear Research in Switzerland. Vetra’s body is found burned onto the chest with the Illuminati’s symbol. Vetra had been working on a project involving antimatter, a substance that has the potential to create a devastating explosion if it falls into the wrong hands.

Maximilian Kohler, the director of CERN requests Robert Langdon to help investigate Vetra’s death. Langdon discovers that the Illuminati, a secret society of scientists that was thought to have been disbanded centuries ago, has resurfaced.

They soon learn that the antimatter canister has been stolen and the Illuminati has claimed responsibility and is threatening to detonate the antimatter in Vatican City, during the papal conclave, a gathering of cardinals who will elect the next pope.

Langdon meets Vittoria Vetra, Leonardo Vetra’s daughter and a scientist who worked with her father on the antimatter project. Together, they travel to Vatican City, where they learn that the four preferiti (the cardinals who are the leading candidates to become the next Pope) are kidnapped by the Hassassin, who plans to blow up the Vatican with the antimatter canister and kill the four cardinals under the orders of “Janus“, the leader of the Illuminati.

The Illuminati threatens to kill one cardinal per hour, and they have hidden the antimatter somewhere within Vatican City, which will explode at midnight.

Believing that the four cardinals will be ritually murdered on the four altars of the “Path of Illumination“, Langdon and Vittoria follow a series of clues left in various churches in and around Rome including the Pantheon, Piazza Navona, St. Peter’s Square and Santa Maria della Vittoria. They race against time to find the antimatter and save the cardinals. Along the way, they encounter a series of challenges and obstacles, including attempts on their lives, hidden codes and puzzles, and the revelation of dark secrets within the Vatican.

The Hassassin kills three cardinals, one by one, burning on their chests the illuminati symbols of ‘Earth’, ‘Air’, and ‘Fire’. Langdon and Vittoria race to the last church, Santa Maria della Vittoria, where they confront the Hassassin, who kills the fourth cardinal, branding him with symbol ‘Water’.

The Hassassin kidnaps Vittoria and take her to the Castel Sant’ Angelo, the Church of Illumination. After a long cat and mouse game, Langdon frees Vittoria and together they send the Hassassin falling several hundred feet to his death.

Meanwhile, Kohler arrives at the Vatican to confront the Camerlengo. Langdon and Vittoria fearing Kohler is Janus, hurry back to St. Peter’s Basilica to prevent him from murdering Ventresca. Kohler is killed firing of Swiss Guard. Just before dying , Kohler gives Langdon a mini video camera which had recorded his confrontation with Ventresca.

The climax of the novel takes place at the Necropolis, the underground ‘City of dead’ beneath the Vatican.  The Camerlengo discovers the antimatter canister atop the tomb of Saint Peter. Ventresca takes the canister to a safe height in a helicopter and parachutes himself safely onto the roof of St. Peter’s Basilica and the canister explodes in the sky, saving the Vatican.

Due to this ‘miraculous act’ of Ventresca, the Cardinals debate whether to elect him as the new Pope. Meanwhile, Langdon learns from the video given by Kohler that Ventresca himself is Janus, working to sabotage the Vatican.

At last, he confesses that he poisoned the Pope upon the Pope’s revelation that he had fathered a child, and because of his opposition with Leonardo’s attempt to bridge science and God. Under the guise of Janus, he recruited the assassin to kill Vetra, steal the antimatter and kidnap and murder the Preferiti.

Cardinal Saverio Mortati, Dean of the College of Cardinals, reveals that Ventresca is, in fact, the late Pope’s biological son, conceived with a nun through artificial insemination. Overcome with guilt, Ventresca soaks himself in oil and sets himself on fire before a crowd of onlookers in St. Peter’s Square. Mortati is unanimously elected Pope by the Cardinals.

As the end of the novel, the last brand, the Illuminati Diamond, is gifted to Langdon by the new Pope with the caveat that he may return it to the Vatican at his will. Langdon and Vittoria enjoyed a memorable night in Hotel Bernini.

INTRODUCTION  THEMES AND MOTIFS  CURIOSITY & SUSPENSE 

CRITICAL ANALYSIS  IMPORTANT CHARACTERS  STRESSFUL MOMENTS & CLIFFHANGERS

DESCRIPTIONS OF KEY OBJECTS, PLACES, ORGANIZATIONS & PROCESSES  MOVIE ADAPTATION