Seven hundred years before the story's start, humankind colonized
Luna, where the Society—a rigid social hierarchy of 14 Colors with specialized roles—was developed for efficiency and order. The Society, harshly ruled by certain families of mentally and physically superior Golds, conquered
Earth and colonized moons and small planets. Reds are the Society's lowest-status laborers.
Mars's underground Red mining colonies compete in rigged contests that sow discord and are lied to that Mars is not yet
terraformed. At the story's outset, 16-year-old Darrow is a rash, intelligent, dexterous, newly-wed Red
helium-3 miner. Darrow and his wife Eo are publicly whipped for visiting a restricted underground forest. With Mars's ArchGovernor Nero present and the event being filmed, Eo sings a song protesting the Reds' enslavement. Nero has Eo publicly hanged. A grieving Darrow illegally buries Eo and is hanged too, but survives due to his uncle Narol drugging him. Narol then delivers Darrow to the Sons of
Ares, who aim to overturn the Society's hierarchy. The Sons used footage of Eo's song and execution as propaganda. Dancer, a Red, wants Darrow to infiltrate the Society as a Gold. Darrow is physically transformed by Mickey (a Violet) via a "carving", physically trained by Harmony (a Red), and taught Gold customs by Matteo (a Pink). Under the fabricated Gold identity of "Darrow au Andromedus", he excels in testing and is accepted into Mars's Institute. He is drafted into House Mars, one of 12 school Houses, where he befriends Cassius. The Institute begins with the Passage where students are beaten, then paired off (a high test scorer with a low test scorer) to fight to the death barehanded. Darrow kills Cassius's brother, Julian, and lies about it. Sevro unexpectedly kills high-status Priam. Next, in the
Valles Marineris, each House is assigned a castle and told to conquer the other Houses. Each school House's flag can enslave other Houses' students. House Pluto, led by Nero's son Adrius ("the Jackal"), resorts to
cannibalism to survive. Darrow wields a
scythe; he is nicknamed "Reaper". House Mars fractures into factions: Darrow and Cassius's, Antonia's, and Titus's. Sevro operates alone. Quinn saves Darrow from Titus's faction. The bloodthirsty Titus rapes enslaved peers and captures Quinn. Cassius challenges Titus but Titus's group assaults Cassius. Darrow manipulates House Minerva, led by "Mustang" (Virginia), into defeating Titus and retreating. Sevro saves Darrow and Cassius from House Minerva. Darrow speaks to a captive Titus and realizes he is a Red that has also undergone a "carving" as an agent of the Sons of Ares. To maintain his cover, Darrow sentences Titus to death. Cassius duels and kills Titus, thinking Titus killed Julian. Darrow outwits and enslaves House Diana and most of House Minerva but lets Virginia escape with her flag, leading the sadistic Vixus away. Adrius's subordinate, Lilath, declares a bounty on Darrow and passes Cassius a pouch that Darrow asks Sevro to steal. Cassius thwarts this and watches the pouch's video of Darrow killing Julian. Antonia, Vixus, and Cassandra use Lea to ambush Darrow. Darrow hides, and they execute Lea and flee. Cassius stabs Darrow in a duel and leaves him for dead, usurping House Mars, but Virginia rescues Darrow. As he recovers, they develop romantic feelings. Virginia falls gravely ill. Fitchner, House Mars's Proctor and Sevro's father, tells Darrow that Nero manipulated the Proctors to help Adrius. Darrow obtains medicine from Fitchner to cure Virginia. Darrow and Virginia amass an army by freeing slaves using House Minerva's flag. When Tactus tries to rape Nyla, Darrow has both Tactus and himself whipped, earning his army’s loyalty. Darrow conquers Houses Ceres and Apollo. Sevro rejoins Darrow, who incapacitates Fitchner for his flying boots. Darrow traps Adrius, who amputates his own hand to free himself. The Proctors help Adrius counterattack and escape, Pax protects Darrow, and Adrius kills Pax. The Proctors kidnap Virginia. Enraged, Darrow slays Proctor Apollo. With the Proctors' flying boots, Darrow's army storms Olympus, the Proctors' base, freeing Virginia and capturing the Proctors. Sevro deletes evidence that Darrow is a Red. Darrow usurps Cassius, who declares a blood feud. Learning that Virginia is Adrius's twin sister, Darrow fears her betrayal, but Virginia dutifully delivers Adrius and Darrow wins the Institute's title. Many Golds covet Darrow. Nero proposes to help Darrow join the fleet-commanding Academy and rise to power if Darrow hides Nero's game-rigging and becomes his Lancer (
aide-de-camp). Darrow agrees, publicly joining House Augustus. ==Characters==