Lysander au Lune, one-time heir presumptive to the Society’s Sovereign, and Diomedes au Raa, Storm Knight of the Rim, discuss Atalantia au Grimmus, the Dictator. They plan to meet with her, but they do not trust her. Seraphina, Diomedes’s sister, does not trust Lysander, and Lysander finds himself oddly attracted to her. Lysander reflects on his long history with Atalantia, knowing he must convince her that he does not want to seize her power. He is nervous about the upcoming meeting between the Rim and Core Golds (the Rim and Core regions of the solar system are similarly hierarchical, but the Rim’s elite felt marginalized by the Core and sought independence from it).

Darrow and Orion meet with Cadus Harnassus, an Orange who is loyal to Darrow despite technically being the ArchImperator of Darrow’s army (the highest-ranking military position and a role Darrow formerly held but was forced to give up following a military dispute with the Senate that resulted in Darrow killing a hero of the Republic). Harnassus and Orion argue while they discuss plans to unearth hidden Storm Gods, or “weather-shapers” for terraforming planets.

Glirastes, “the Master Maker of Mercury” and thus one of the most highly skilled Oranges (24), is hesitant to use the Storm Gods, but Darrow argues that he will be careful not to destroy the planet. With Orion acting as pilot, they successfully launch a Storm God.

Lysander, Diomedes, and other representatives of the Rim land on the Annihilo to meet with the Core Golds. Lysander recognizes Kalindora and Ajax—the White and Storm Knights of the Core, respectively. He proves his identity by offering his finger to be pricked with a poison that is DNA-triggered, after which Ajax welcomes him warmly. Ajax is territorial toward Diomedes, who serves as the Storm Knight in the Rim Dominion. He forces Diomedes to remove the Storm God crest and then urinates on Diomedes’s cloak, which Lysander recognizes as a strategy called “Requisite Disrespect.”

Darrow briefs his army on Operation Voyager Cloak—a plan to draw in the Society army, which currently has the Republic’s forces pinned on Mercury, for a surprise attack—and on Operation Tartarus, which involves the Storm Gods. Harnassus is upset by the plan but agrees.

As they speak, Alexander calls through the communications network that Atlas did not fall for Operation Voyager Cloak and that the city of Angelia is under attack. Darrow sends Harnassus to hold Heliopolis and Orion to operate the Storm Gods, making her promise to keep the machines below the horizon to temper them. Once Orion leaves, Darrow shows Rhonna a switch he is carrying—his “insurance plan” to keep Orion in check.

Atalantia greets Lysander, forcing him to kiss her pet snake. They meet with Ajax, Kalindora, and the leaders of the remaining Conquering Golds (descendants of those who originally instituted the Society)—Carthii, Falthe, and Votum. Scorpio au Votum is skeptical of Lysander's reappearance, prompting a threat from Atalantia. Lysander explains that at the time of the coup that instituted the Solar Republic, Darrow would have killed him; however, a Gold named Cassius au Bellona intervened and instead received Lysander as a ward. Cassius is now dead following a duel he fought against Seraphina (or so Lysander believes), and his body has been desecrated.

Diomedes and Seraphina join the meeting to secure a truce between the Rim and Core Golds. Atalantia questions whether Lysander has plans of overthrowing her, which he denies. She agrees to a truce, though the terms of the deal are yet to be solidified, and she shares food with her visitors in a symbolic act of protection. The discussion turns to their plans to attack Mercury with an “Iron Rain” of soldiers fired from ships into battle on the planet’s surface. Atalantia asks Diomedes to fight, but he refuses, saying he was sent as a “voice.” However, Seraphina offers to take part in the Iron Rain.

After the meeting, Ajax hits Lysander for serving as a ward. Apologizing, Lysander says that he was scared to return after witnessing so much violence among the Golds. He has returned now because he hopes the violence can end if the Society defeats the Solar Republic. Still skeptical, Atalantia decides to keep Lysander’s return quiet. Although he does not want to be Atalantia’s rival, he recognizes his claim to authority as heir of the previous Sovereign, Octavia. To demonstrate his loyalty, Lysander says he will take part in the Iron Rain and earn a scar (Golds receive ceremonial scars in recognition of honor or might, particularly in battle).

Darrow and his team find Alexandar and Thraxa, who have been following Atlas, as well as the “forest” of bodies—dead and dying—left for them by Atlas. Alexandar lost track of Atlas when he fell asleep driving after staying awake for 140 hours and living off stimulants. Darrow initiates Operation Tartarus.

An intimidated and anonymous Lysander prepares for the Iron Rain, reflecting, “I am thrust into an assembly line of muscled predators” (61). Pytha, a pilot, tells Lysander that he will die in battle and is upset to learn he volunteered. Lysander explains that he wants to help maintain humanity’s unity and that to do so, he must gain respect by earning a scar. Pytha counters that Lysander must evoke fear, not respect, arguing that Lysander’s grandfather, Lorn au Arcos, seemed honorable but “was death incarnate” (63). Lysander does not want to spread fear, which is why Pytha thinks he will die.

The Whites perform a traditional Blood Benediction ceremony before the Iron Rain. The ceremony riles the soldiers, but Lysander tries to suppress the “human flaw” of violence. The soldiers then undergo a briefing and learn that their plans are to take Heliopolis, a move that makes Lysander and Seraphina realize Atalantia plans to betray Scorpio by seizing control of Mercury, which Scorpio’s family formerly controlled. Lysander parts from Ajax and Seraphina, noticing Seraphina’s troubling bloodlust.

Darrow reflects on Atlas and on the Senate’s inaction before approaching the bodies left by Atlas in Angelia. Darrow stops Alexandar from helping any survivors, warning him that they will be “booby-trapped.” He sends a team to search for traps and tells the surviving individuals, who have been impaled, that a medical team will come for them. He then leaves for Angelia’s communication center, where they see the gory aftermath of a potential biological attack.

Alexandar calls Darrow to come to the refinery, showing him how the cities are connected by mines, which accounts for Atlas’s entry. Darrow calls for an evacuation of Angelia, and then the bombs Atlas planted in the city begin to detonate.

Harnassus calls and requests permission to retreat from Heliopolis. Darrow formulates a new plan. Thraxa is to meet him in Tyche when he signals her with a double atomic explosion. Alexandar stares at the destruction, and Darrow understands that he blames himself. He hits Alexandar and sends him to deliver orders; he then calls Orion and asks if she can delay the effects of the Storm God for an extra 10 minutes. Over the communications network, Darrow delivers a widespread briefing and pep talk. When he finishes, atomic bombs start to detonate.

Atalantia signals the start of the Iron Rain, and Lysander feels terror instead of glory: “Every frayed nerve, every quaking cell, screams in horror, urging me to crawl out of the tube” (77). He uses the Mind’s Eye—a state of total awareness—picturing Octavia teaching him to suppress his fear. He is fired from the ship, and though at first shocked by the physical sensations, he is then able to absorb the “grandeur” of the experience.

As he nears the surface of Mercury, he is disturbed by the heavy use of atomic weapons: “Particle beams divide reality. Mushrooms bloom on the surface” (81). He lands in the chaos of battle.

The atomic bombs are followed by a large air raid of 600 ripWings (small aircraft). As Colloway evasively flies the Necromancer, Harnassus offers support. Darrow is hit in the shoulder, and his suit delivers an automatic adrenaline injection. They arrive at Red Reach, a Republic base, and Darrow dons heavy starShell armor. Watching bombs about to impact, Darrow delivers a parting speech to the people about to die. The bomb destroys his Second Army, and Darrow blames himself: “The hollow abyss of despair calls to me” (90).

Alexandar comes to Darrow for new orders. Darrow calls Orion, sending her to Kydon (a city in northeastern Helios) to find Thraxa and send her to Tyche, and he gathers the remaining members of the Second Army. He equips them with starShells and Drachenjagers (mechs), and they depart to defend Tyche.

Lysander’s reality fragments from the chaos of battle. He is upset when the Society bombs a town of civilians, which Ajax writes off by arguing that the people were “sympathizers.” While resting in the desert of Ladon—the “army eater”—Lysander cleans his starShell and talks to Kalindora, who argues that cruelty is inevitable in war and that they had no way of knowing if the town that was bombed was armed or rigged.

Society soldiers organize and prepare for attack. Lysander sees Rhone, formerly one of his family's House supporters, who now serves as one of Julia au Bellona’s Praetorians (personal guard). Rhone declares his loyalty to Lysander and tells him that Julia released her Praetorians from service as an act of loyalty to Lysander, which Lysander worries Atalantia will view as a challenge.

Ajax delivers a brief of their plans to take Heliopolis but is interrupted by reports of extreme weather—several hypercanes with 800 kph winds. Lysander, knowing there are Storm Gods on the planet, urges them to wait out the storm. They take cover as they are hit by a massive sandstorm, which kills several people and damages their supplies. Ajax falls to the ground, and Lysander reflects on the first time he saw Ajax scared, while trying and failing to cross a dangerous bridge.

Later, Lysander explains that Darrow is using Storm Gods, making the others question why Octavia hid Storm Gods on Mercury. Ajax insists they push forward toward Heliopolis.

Darrow and his soldiers move forward through the storm, using it as cover for a surprise attack on the recently landed Society armies. Darrow finds and kills Scorpio as they push forward toward Tyche.

Lysander, followed by Kalindora, Seraphina, and 1,000 Praetorian soldiers, leads an expedition to find and disable the Storm God responsible for the sandstorm in Ladon. Taking Seraphina’s advice, they tie themselves together to avoid getting lost in the storm; however, they make slow progress and lose several Praetorians. Lysander feels less fear as his survival drive kicks in, providing him with clarity.

Lysander and the others run into a band of Votum allies. In a tense moment, Kalindora argues with Cicero, a calculating Rim Gold, and Lysander diffuses the situation, revealing his identity. They plan to join forces to stop the Storm God and then move on together to take Heliopolis.

The Society soldiers arrive at the eye of the storm. Lysander believes that “Darrow is no longer a good man” (113), having turned a machine of creation—the Storm God—into a weapon. As they are preparing, Seraphina is killed by enemy fire.

Darrow arrives at Tyche, which is being battered by a hypercane. He realizes that Orion has either lost control of the Storm God or has disobeyed orders. He calls her and finds that all but one of the people with her are dead; Orion has turned the Storm God to level four to “teach” the Society loyalists who live in Tyche. She refuses to stop, so he initiates the override switch, which kills Orion; he then disables the Storm God.

Alexandar asks permission to help the civilians in Tyche, which Darrow refuses. Rhonna brings Screwface—an undercover Howler (an elite military rank)—to Darrow. Screwface tells Darrow that Heliopolis is under attack, and Darrow tells him about Orion’s death. Darrow must choose between attacking Society forces and saving his remaining armies, and he opts for the latter. He announces they will defend their remaining stronghold, Heliopolis, meaning they must cross the Ladon. Darrow grants Alexandar’s second request to stay and help those in Tyche.

Lysander wakes, his starShell low on oxygen, and digs himself out of sand. Ajax was supposed to extract him and his companions but is late, and they do not have enough functioning starShells for the remaining soldiers. Lysander finds Rhone and a dying sunblood horse, which Rhone kills. Spying Kalindora on a dune, Lysander goes to her and learns that there are Drachenjagers approaching their location.

They return to the fallen Storm God, where communications have been restored; Ajax announces that he is not coming for them. Rhone explains that Lysander and a few others could be evacuated, but Lysander asks to know the names of the deceased soldiers who had been assigned as his wingmen, refusing to leave his remaining Praetorians to die. A scout approaches their location, and then they hear the howling of Darrow’s Howlers.

Darrow and his soldiers tear through Lysander’s Praetorians, having snuck around to attack them from multiple directions. Lysander watches Darrow fight: “He pulls violence toward him, drinks it into his current, and leaps around the battlefield with a seemingly mindless capriciousness” (132). Lysander calls for the Praetorians to kill Darrow, but Darrow attacks Lysander, and he falls to the ground. As Darrow moves on, Lysander gets stuck next to a piece of equipment that burns through his helmet and face.

Moving on from the Storm God in Ladon, Darrow continues toward Heliopolis, though his forces’ armor and supplies have been severely depleted, and they are running on stimulant drugs. The storm at Tyche is still raging, and Darrow lost one-third of his army while traveling through the sandstorm. They arrive outside the city, and it seems as if the Society has taken it.

While they are surveying the scene, Atlas attacks, ordering his soldiers to extract Darrow from his armor, humiliate and torture him, and kill him. As the soldiers attack, Darrow is initially overcome with fear but then realizes he can take advantage of the lightened gravity to fight back. He frees himself, killing Atlas’s soldiers just as Thraxa and the Morning Star appear to defend Heliopolis. Darrow dons fresh armor, and the Solar Republic armies viciously defend Heliopolis. Ajax flees, and Darrow fights until he collapses. Harnassus insists that Darrow get medical treatment while he and the other leaders manage the battle. Darrow wakes after receiving treatment, and Thraxa enters and announces their victory.