Anathem

by Neal Stephenson

Anathem is set on and around the fictional planet Arbre. Thousands of years before the events in the novel, the planet's intellectuals entered concents (monastic communities) to protect their activities from the collapse of society. The avout (intellectuals separated from Sæcular society) retain extremely limited access to tools and are banned from possessing or operating most advanced technology and are supervised by the Inquisition, which answers to the outside world. The avout are allowed to communicate with people outside the walls of the concent only once every year, decade, century, or millennium, depending on the particular vows they have taken.

The narrator and protagonist, Fraa Erasmas, is an avout at the Concent of Saunt Edhar. His primary teacher, Fraa Orolo, discovers that an alien spacecraft is orbiting Arbre – a fact that the Sæcular Power attempts to cover up. Orolo secretly observes the alien ship with a video camera, technology that is prohibited for the avout. Erasmas becomes aware of the content of Orolo's research after Orolo is banished (in a rite called Anathem) from the Mathic World for his possession and use of proscribed technology within the concent. But the presence of the alien ship soon becomes an open secret among many of the avout at St. Edhar. The alien ship eventually declares its presence by shining a laser upon the Millenarian Math of Saunt Edhar, the bastion of those avout who have taken a thousand-year vow not to interact with the outside world. Shortly after that, the Sæcular Power evokes (calls forth) many avout from Saunt Edhar, including Erasmas, as well as one Millenarian – Fraa Jad.

Erasmas and several companions, on Fraa Jad's suggestion, decide to seek out Orolo. After a dangerous journey over the planet's frozen pole, undertaken to reach another continent without passing through national borders, Erasmas and his comrades eventually arrive at a concent-like establishment called Orithena – which is on the site of the ancient source of the Mathic world – where they reunite with the no-longer Fraa Orolo (he being Anathematized). Orolo holds discussions with Erasmas about the nature of the cosmos and consciousness, and how he believes that the aliens are not simply from another planet, but from another cosmos that is influenced by Arbre. During the discussions between Orolo and Erasmas, a small spacecraft lands in Orithena, on the very site of the ancient Mathic world's Analemma, which is visible from space. A female alien is on board, but dead of a recent gunshot wound. She has brought with her four vials of blood – presumably that of the aliens – and much evidence about their technology. Shortly thereafter, the aliens propel a massive metal rod at a nearby volcano, triggering an eruption that destroys Orithena. Orolo sacrifices his life to ensure the safety of the dead alien's remains and her blood samples, an event that leads to his canonization as Saunt Orolo.

Erasmas then travels to the concent of Saunt Tredegarh – where he was expected to have gone when evoked – to attend the Convox. This is a joint conference of the avout and the Sæcular Power, dedicated to dealing with the military, political, and technical issues raised by the existence of the alien ship in Arbre's orbit. Tredegarh is where the Sæcular Power had brought the evoked avout of Saunt Edhar and from many other concents from all around the world to work on methods of interpreting the limited information regarding the alien spacecraft, as well as investigating possible military options. Much research is done on the samples Orolo sacrificed his life to save, and the aliens are found to come from planets in four parallel and distinct cosmos: Urnud, Tro, Laterre and Fthos. The multiple-worlds interpretation of the cosmos is discussed in great detail by the high-level avout at successive evening meals to which Erasmas performs the duties of a servant. In this section of the novel, it slowly becomes plain that Laterre is our own Earth, which serves as a 'higher plane of existence' for Urnud and Tro, and Arbre is itself a 'higher plane' for Laterre. Through observation and experiment, Erasmas and his companions determine that the conference is infiltrated by the aliens, and unmask a French-speaking Laterran linguist by the name of Jules Verne Durand. He explains that the aliens are experiencing internal conflict between two factions. The currently ruling faction (the more militaristic 'lower worlds' Urnud and Tro, as well as some Laterrans) intends to attack and raid Arbre for its resources in order to repair their spaceship, while the opposing faction ('the higher world' Fthos and most Laterrans) favors open negotiation. Jules Durand offers to assist the avout of Arbre in resisting the ruling faction of the aliens, believing that they can bring the situation to a peaceful conclusion.

Fearing alien attack after Durand has been exposed, the avout evacuate Saunt Tredegarh and all the other concents on Arbre simultaneously. Erasmas and his comrades are taken to a distant sanctuary, where they receive training for a mission to board the alien ship and disable its weaponry. They are launched into space – on ballistic missiles built for planetary nuclear warfare – unknowingly bringing with them "Everything Killers" (miniaturized Neutron Bombs) that the Sæcular Power intends to use as a last resort should the primary goal of the mission fail. Three people – including Fraa Jad – are issued detonators.

Upon arrival at the alien ship, they are preparing the ship's main weapon. Avout from the Ringing Vale, who dedicate their lives to study of the martial arts and military tactics, head off to destroy the ship's main weapon. They are ultimately successful but perish in their attack. The narrative now parallelizes (across multiple variations of the multiple cosmos of Arbre) as the avout team boards the ship and pass out from breathing the alien oxygen. In one Narrative, Fraa Jad awakens Erasmas and leads him through the ship toward the command center. Jad opens the accessway to the command center on the first try and, upon being attacked by alien soldiers, triggers the Everything Killers killing himself, Erasmas and everyone in that area. The Narrative immediately jumps back to the same accessway but this time Jad doesn't guess the lock code, and instead the soldiers take them captive and bring them to parley with the leader of peaceful faction, where it emerges that the Millenarian avout of hundreds of years in the past may have used their "incanting" powers to summon the ship to their cosmos from another universe.

In the final Narrative (the one that continues forward) Erasmas awakens in a hospital on the starship to the perplexing news that Fraa Jad had died immediately after their launch, contradicting his obvious presence and Erasmas' memories up to that point. It remains unclear which (or how many) of these contradictory narratives is real, and what may have happened in different worldtracks that have crossed and overlapped. However, Fraa Jad had hinted that the Incanters (and possibly Rhetors) were capable of operating simultaneously in parallel universes, so Jad is likely to have survived in other versions of the world.

Erasmas learns that the aliens have brought up a delegation of diplomats from Arbre. A funeral ceremony for those lost on both sides of the attack forms part of the signing of a peace treaty between the aliens and the Arbrans. On Arbre itself, the Sæcular Powers and the avout have agreed to cooperate as equal powers. The people of Arbre inaugurate a second "Reconstitution", revising many of the rules that had restricted the work and lifestyle of the avout. Erasmas and friends set about the task of building a new concent, dedicated to Saunt Orolo.