The ice hauling ship
Canterbury is en route from
Saturn's rings to
Ceres when it encounters a
distress signal. Five members of the
Canterbury's crew are dispatched in a shuttle to investigate: executive officer James "Jim" Holden,
chief engineer Naomi Nagata, pilot Alex Kamal, engineer Amos Burton, and medic Shed Garvey. They discover an abandoned transport vessel called the
Scopuli, and find that the distress beacon which lured them is fake and contains Martian technology. An unknown
stealth warship arrives and, without warning, destroys the
Canterbury with
nuclear weaponry. Holden broadcasts a message out to the entire solar system implicating Mars in the destruction of the
Canterbury, starting a war between Mars and the Belt. The survivors of the
Canterbury are ordered to rendezvous with the Martian battleship
Donnager. The ship's captain denies any knowledge of Martian involvement in the attack on the
Canterbury. The
Donnager is attacked by ships of the same unknown design and destroyed. While Holden and most of his crew manage to escape on a Martian frigate, Shed is killed. The ''Canterbury's'' surviving crew flee to the protection of the OPA's leader, Colonel Fred Johnson. Analysis of a data chip recovered from the
Donnager reveals that the mysterious stealth ships were built by Earth. Holden makes another public broadcast sharing this information, hoping to ease the tensions created by his prior implication of Mars. This massively backfires, instead drawing Earth into the war. The Martian frigate Holden's crew escaped on is renamed the
Rocinante and on it, Holden is sent to
Eros Station to find an OPA operative who sent out a distress signal. On Ceres Station,
detective Joe Miller is illicitly
contracted to locate Julie Mao, the daughter of very wealthy Lunar citizens, and send her back to her family against her will. Miller is warned both by his superiors and OPA operatives to stop looking into her disappearance, and is fired when he refuses. Miller discovers that Mao had been involved with the OPA and was aboard the
Scopuli when it disappeared. Realizing that Mao's disappearance is connected to the destruction of the
Canterbury, he travels to Eros to meet Holden and the crew of the
Rocinante. On Eros, Miller finds Holden's crew and helps them survive an ambush attempt. They locate the body of Julie Mao in a hotel shower infected with a strange, organic growth. On her phone Miller finds logs detailing the progression of her affliction, which seems to be fueled by exposure to
energy and
radiation, and the coordinates of an asteroid where one of the ships that attacked the
Canterbury is docked. Before Miller and the crew of the
Rocinante can leave Eros, a station-wide radiation alert is issued and security begins herding people into the numerous radiation shelters. Miller and Holden discover that the radiation alert has been faked by Eros's security contractor, the Earth-based company Protogen, and that people in the shelters have in fact been infected with the same disease as Julie. The
zombie-like infected people attack the rest of Eros, spreading the infection via
vomit. Miller and the crew of the
Rocinante narrowly manage to escape the station. Miller and the crew of the
Rocinante follow the coordinates from Julie's phone to find one of the stealth ships abandoned. The team finds a Protogen video explaining that the infection is in fact a molecular biological
replication mechanism created by
extrasolar aliens with the intent of reaching Earth and hijacking its early
biosphere in order to create something for its own mysterious purposes, but which had been captured by
Saturn's gravity and stranded. Protogen, which had discovered the organism on Saturn's moon
Phoebe and dubbed it the "protomolecule," orchestrated its release on Eros as an
experiment in an attempt to discover what it was designed to do given a rich biological source. To this end they had carried out the
false flag attack on the
Canterbury in order to start a war which would distract the Solar System from the criminal operation on Eros. With the OPA, Miller and the crew of the
Rocinante attack Protogen's secret base in the belt. They capture lead scientist Antony Dresden, who reveals he believes the Protomolecule is humanity's key to the stars, and that by modifying it for their purposes, humanity could become gods. Realizing that Dresden's rationale is likely to be accepted by the powers that be on Earth and Mars, and thus that this horrific research would be allowed to continue, Miller
summarily executes Dresden without warning, angering Holden. Realizing that it is likely that the Protomolecule will be sought after by malicious actors in the future, the OPA and Miller plan to crash a large ship into Eros to propel it into the
Sun. Miller leads a team onto the exterior of Eros to rig the station with bombs to ensure no one can capture it while en route. Miller, deciding he has completed everything he wanted in life, stays behind on Eros. Just before the ship impacts the station, however, the trajectory of Eros is suddenly and inexplicably altered. The Protomolecule proves to have an advanced method of
spaceflight which negates both
g-force and
inertia. Eros, being driven by this inexplicable force, sets off on a collision course with Earth at a speed that no human-made ship can match. Miller, still on Eros, takes one of the bombs into the station in an attempt to destroy its maneuvering capabilities. However, he realizes that Eros is being guided by Julie Mao, whose infected body is in a
symbiotic relationship with the protomolecule. Although she is being used by the Protomolecule, she retains enough agency for Miller to convince her to direct Eros away from Earth. The station instead crashes into
Venus, presumably killing both Miller and Mao. On Venus's surface, the Protomolecule promptly begins assembling a vast, mysterious structure. ==Reception==