In Angels and Demons (2000), Dan Brown introduces Robert Langdon, the Harvard symbologist who would later star in Brown’s worldwide best seller The Da Vinci Code (2003). The two books share numerous characteristics. Though fictional, both novels claim to be built upon a base of researched facts. Both seek to revise aspects of generally accepted histories, especially those related to the Catholic Church and its relationship to free thought. And both books put Langdon in the middle of violent interactions among shadowy factions, clashes whose outcomes may well determine the future course of Western civilization.

The two books differ in setting, threat, and focus. While The Da Vinci Code tackles ancient speculations about the Holy Grail, Angels and Demons involves more standard thriller fare. It puts science and religion into conflict by reviving the Illuminati, a secret society of scientists and freethinkers whose relationship with the Catholic Church has long been, Brown indicates, intimate, tangled, and not fully known. This secret society returns as a threat when the major church leaders are gathered at the Vatican to elect a new pontiff. Increasing this centuries-old tension is a more specific threat: the Illuminati claim to have stolen a rare sample of antimatter and hidden it somewhere in the Vatican. It is highly explosive if it comes in contact with normal matter, and it will do so when a protective magnetic field runs out in twenty-four hours. Add to this the fact that the four preferred candidates for the papacy have been kidnapped, and the result is that Robert Langdon must decipher a grand puzzle and save the day while half a dozen clocks are ticking. Although the novel’s style is melodramatic, and its exposition and moral judgments are heavy-handed, Angels and Demons remains a first-rate thriller.

When physicist Leonardo Vetra is found murdered with the word “Illuminati” branded onto his chest, Maximilian Kohler, the director of CERN (European Council for Nuclear Research), contacts Harvard symbologist Robert Langdon for help. Kohler has Langdon flown to CERN. Langdon explains the role of the Illuminati—a secret society of artists, scientists, and freethinkers—as a long-standing enemy of the Catholic Church. While Langdon is explaining this, and learning more about Vetra’s research, Vetra’s adopted daughter, Vittoria, who is also a physicist, joins them.

Vittoria and her father had created antimatter in a CERN lab. This was doubly important to her father because he was a priest, and the discovery promised to give humanity access to the secrets of creation. However, it is also a great threat because antimatter explodes when it comes into contact with normal matter. This becomes a pressing issue when they learn that their biggest sample has been stolen, and the battery that generates the magnetic field (and keeps the antimatter stable) has only a twenty-four-hour life span.

CERN is then contacted by the Vatican: a threat has been issued indicating that the antimatter is hidden at the Vatican. This is especially dangerous since a Conclave is being held to elect a new pope to replace the one who recently died. Kohler cannot go immediately because of his poor health, but Langdon and Vittoria make the journey. However, the pair find it impossible to convince Olivetti, the head of the Swiss Guard, that the threat is real. In fact, the commander locks them away while he investigates. Langdon uses his knowledge of Vatican protocol to get them released, appealing to the “camerlengo” (the pope’s chamberlain), who is in charge until the election of the new pope is complete. While they are pleading their case, a representative of the Illuminati calls. He tells them that not only is the antimatter hidden in the Vatican, but the Illuminati have kidnapped the four cardinals who are the favorites to be elected as the new pope. They will kill them, one per hour, at 8, 9, 10, and 11 p.m., at churches around Rome, building the threat before the bomb goes off at midnight, destroying the Vatican, killing many of its leaders, and incinerating much of its wealth.

The camerlengo and the commander of the Swiss Guard decide to let the Conclave continue while they search for the bomb and the missing cardinals. In the Vatican archives, Langdon finds clues to where the cardinals will be killed in a manuscript by Galileo. (The murder sites will be located at places important to the Illuminati, and each candidate will be killed according to one of the four elements: earth, air, fire, and water.) Langdon leads the Swiss Guard to the Pantheon. Langdon and Vittoria enter the church. However, through a conversation with the church caretaker, Langdon realizes they are in the wrong place. They race to Santa Maria del Popolo but arrive too late. They find the first cardinal dead—partially buried in the earth, suffocated with dirt, and branded ornately with the word “earth.”

Langdon and Vittoria discover where the second killing will be and race to St. Peter’s Square, where they find another body, this one more recently killed and branded with the word “air.” As they seek the third site of assassination, the pair are helped more actively by Olivetti, but greater pressure is added by the media, whom the assassin has alerted. The Illuminati claim responsibility for the deaths of the two cardinals and for that of the recently deceased pope.

The camerlengo inspects the pope’s body and finds that he was indeed assassinated. While the camerlengo performing the examination, Langdon returns to the archives for more clues. He is trapped when someone kills the power, so he has to smash his way out of the archives’ glass walls. He and Vittoria go to the Church of Santa Maria della Vittoria. When they arrive, the third cardinal is still alive, but the church is on fire. They try to save the cardinal and capture the assassin, but the killer is more skilled than they are. Langdon has to hide in a crypt to keep from being killed, and Vittoria is captured.

While Langdon and Vittoria are fighting to save the cardinal, the camerlengo makes a public address, admitting that the Illuminati and science have beaten the church, but that in doing so, they have removed meaning from the world. Once the firemen free Langdon, he discovers that the final killing will occur at Piazza Navonna, at the Fountain of the Four Rivers. He races to free Vittoria, save the last cardinal, and capture the assassin. He manages to wound the assassin but is otherwise unsuccessful. However, Langdon does fool the assassin into thinking Langdon himself is dead, and so manages to surprise him by deducing the assassin must be hiding in Castel Sant’Angelo, which is also the ancient, secret Illuminati hideout. Langdon infiltrates the building, has a face-off with the assassin, and is almost killed one more time before Vittoria, having freed herself, burns the assassin with a torch, causing him to fall off the balcony to his death.

Langdon and Vittoria decide that Kohler—the director of CERN—must be Janus, the spy for whom the assassin was working. They race into the Vatican to expose him and save the camerlengo. They find the camerlengo still alive but already branded. The Swiss Guard shoot Kohler dead. They start to take the camerlengo to the hospital, but he suddenly seems inspired. He races into St. Peter’s, where he finds the antimatter bomb.

Realizing it is too late to get the bomb back to CERN, or to a safe distance by land, the camerlengo, who flew helicopters in the military when he was younger, takes a helicopter. Langdon jumps in. The two men fly the helicopter high into the sky. The camerlengo locks the bomb in the chopper and parachutes out. Langdon dives from the machine into the Tiber River.

The bomb goes off far above Rome. The Vatican and the city are saved. The camerlengo is hailed as the savior of the church. However, Langdon shows up with a video Kohler had made of his discussion with the camerlengo. The video reveals that the camerlengo spoke with Leonardo Vetra about his discovery of antimatter before his murder. The camerlengo admits that he was behind the resurrection of the Illuminati—and that he arranged the deaths of Leonardo Vetra, the four cardinals, and even the pope, whom the camerlengo thought had proven himself to be weak and sinful because he had fathered a child. However, in another surprise reverse, it is revealed that the child was fathered in a lab, not through sex, and that the pope never broke his vows—and that the camerlengo is the child. Heartbroken, and realizing how wrong his actions were, the camerlengo goes out onto a balcony facing St. Peter’s Square, lights himself on fire, and falls to his death.

Robert Langdon and Vittoria Vetra, who have grown close during their adventures, end the book with a sexual encounter and perhaps a budding romance.