The unexpected stalemate at the Iserlohn Corridor urges the Imperial Headquarters to muster a reinforcement fleet to be immediately sent in support of Reuenthal. Or at least this is what the Imperial crews believe... but as the fleet jumps out from subspace, it becomes clear that Iserlohn is not their destination. Then Mittermeyer, commander of the fleet, announces that they are about to turn the page in the book of history. On Fezzan, people are staring overhead with anxiety as the sky is filled with ships.

An Alliance relief fleet is finally heading to the Iserlohn Corridor, but combat forces on the battlefield are limited, and a wrong move could turn fatal. Should the Iserlohn garrison fleet be unable to break the blockade imposed by Kempff's ships, the reinforcements from Heinessen would be easily destroyed. On the command bridge of Iserlohn, Caselnes and his officers animatedly discuss the countermeasures, but what sounds like the best plan comes from somebody most unexpected.

The Imperial fleet relentlessly conducts their assault on the Iserlohn Corridor, one blow after another. As Caselnes is still struggling with organizing an effective resistance, Imperial armored infantry units have landed on Iserlohn, and threaten to establish a bridgehead. Then, former Imperial admiral Merkatz, who defected to the Alliance, asks to be assigned temporary command of the garrison fleet.

The battle against the Lippstadt Nobles Coalition has ended, and a victory celebration and audience with the war prisoners is being held at Geiersburg Fortress. The guards forbid Kircheis from carrying his firearm inside, even though he always had permission to keep his weapons in Reinhard's presence before. As the war prisoners face Reinhard one by one, Braunschweig's adjutant, Ansbach, enters with his leader's body in a coffin...

The Free Planets Alliance Navy Expeditionary Fleet is fighting a severe supply shortage, and the supply convoy that was sent to save them has been destroyed by Kircheis in a fierce attack. Without their desperately needed supplies, the disheartened Alliance fleet takes a hard hit from the Imperial Navy. As Reinhard's subordinates take out the Alliance fleets one by one, Yang's 13th Fleet is attacked by the Kempff Fleet.

When the massive Geiersburg Fortress suddenly materializes in the Iserlohn Corridor, Caselnes immediately forwards a request for reinforcements to Heinessen, but now he must prepare for the imminent Imperial attack. Meanwhile, in Heinessen, Frederica is desperately looking for allies to save Yang.

A massive fleet led by Oskar von Reuenthal appears in the Iserlohn Corridor. Boasting overwhelming numerical superiority over the defending Alliance forces, the Imperial commander is confident he can crush his opponent in a quick and easy victory. Back on Heinessen, Bewcock warns admirals and MPs that the Empire may be following a less-obvious strategy this time, thus immediate action must be taken to avert the worst. And Yang realizes that his greatest problem of all may not be the approaching enemy ahead, but the supposed friends behind him.

The Imperial invasion force returns to the capital Odin, where Reinhard shows very different treatment to the personnel involved in the operation. Meanwhile, dissatisfaction with the new leadership is unexpectedly growing in the heart of one who was once the Empire's most loyal war hero. At Iserlohn Fortress, where peace has temporarily been restored, Yang and Julian have a very frank conversation, and Julian reveals the path he has chosen.

Schönkopf and his subordinates from the Rosen Ritter successfully infiltrate Iserlohn Fortress by disguising themselves as Imperial soldiers on the run from the Alliance. He requests an audience with the fortress's commander, saying he wants to relay some vital information acquired during an espionage mission. The commander, Admiral Stockhausen, gives permission, but the captain of the control room guard grows suspicious.

Admiral Kempff, Commander-in-Chief of the Geiersburg Imperial expeditionary force, sends a peremptory declaration of war to the Alliance garrison of Iserlohn. Then Geiersburg's main gun suddenly opens fire with devastating results. On Iserlohn, a confused Caselnes and his officers do not seem to agree on the best strategy to take...

Only a short time has passed since the Alliance's failed invasion of the Empire, and an assassination attempt on Admiral Cubersly, a key figure in the Alliance Navy, further deepens the people's anxiety. On top of that, an accidental explosion the following day takes fourteen young soldiers' lives. Growing discontent has caused revolts to break out on several planets within the Alliance. Bewcock orders Yang to put down these revolts, but before Yang has a chance to deploy, a coup d'état is executed on the capital planet Heinessen.

In humanity's distant future, two interstellar states—the monarchic Galactic Empire and the democratic Free Planets Alliance—are embroiled in a never-ending war. The story focuses on the exploits of rivals Reinhard von Müsel and Yang Wen Li as they rise to power and fame in the Galactic Empire and the Free Planets Alliance.

In a sudden public speech from Heinessen directed to all citizens, Chairman Trunicht announces that epoch-changing events are occurring as a most unexpected defector has arrived seeking protection under the ideals of freedom and democracy in the Alliance. Everyone on Iserlohn is puzzled, but Yang has a hunch that makes him feel aggravated. Then, news from Odin casts an ominous shadow across the entire galaxy.

With the return of Yang to the battlefield, the Imperial fleet increasingly loses momentum and is now on the verge of collapse. Admiral Kempff has to come to terms with the fact that his forces are no longer capable of holding the front line, and sends an order of general retreat to all ships. But this is not necessarily an admission of defeat, because he has one last card to play.

Annerose, Reinhard's older sister, lives in the palace as the kaiser's favorite mistress. As Reinhard and Kircheis make their way to her residence for a visit, they both recall memories of their childhood together. Then Annerose, after greeting them with a smile that hasn't changed since they were young, asks Kircheis to continue looking out for her brother and guide him back toward the right path if he ever goes astray.

The head of the Galactic Empire's Science and Technology Department, Anton Hilmer von Schaft, is a man known for his sheer ambition. He is now presenting to Reinhard a large-scale plan to retake the long-lost Iserlohn Fortress.

Oskar von Reuenthal ran out in a stormy night to seek help from Reinhard von Lohengramm (then Müsel), a rising star in the Imperial Navy that was also known to be disdained by the high nobles. During the meeting with Reinhard and Siegfried Kircheis, Reuenthal convinced Reinhard to save Wolfgang Mittermeyer, in exchange for the absolute loyalties of both of them to Reinhard. Mittermeyer was promptly freed from captivity, and together with Reuenthal, became the first people outside Kircheis to join Reinhard's cause. Back in the present, Reinhard is busy consolidating his authority as supreme commander of the Imperial Navy and prime minister of the Galactic Empire, and to facilitate that he expands the number of commanders under his direct command.

Wolfgang Mittermeyer and Oskar von Reuenthal, two renowned admirals under the command of Reinhard von Lohengramm collectively dubbed as the "Twin Pillars", get together and reminisce about their respective pasts, culminating in the event that would lead to the defining moment of their careers: the Klopstock Incident. In March 795 UC, after thirty years of life in exile from Imperial high society, Marquis Wilhelm von Klopstock plotted an assassination of Kaiser Friedrich IV that was to occur during a party organised by Duke Otho von Braunschweig.

As if to fill the void caused by the death of Siegfried Kircheis, Reinhard von Lohengramm devotes his energies entirely on reforming the Galactic Empire. His wide-ranging reforms earn him tremendous goodwill from the populace, and despite considering them to be publicity stunts, even his sceptics are suitably impressed by the breadth of the reforms.

The planet Fezzan is an autonomous dominion located in one of the only two safely navigable zones that connect the Galactic Empire and the Free Planets Alliance. Every Fezzani head of state, or Landesherr, has protected the independence of the dominion by maintaining strong ties with both its much more powerful neighbors. However, the current fifth Landesherr, Adrian Rubinsky, also known as the Black Fox of Fezzan, seems intentioned to change this long-standing policy.

A meeting is underway at the Free Planets Alliance Navy Integrated Tactical Operations Center to plan the Alliance's large-scale invasion into Imperial territory. Commodore Falk, an operations staff officer, proposes a plan, but Vice Admirals Bewcock and Yang raise concerns about the dangers of invading with widely separated forces and an excessively long supply line. Meanwhile, Reinhard is concocting a plan to draw the Alliance Navy deep into Imperial territory and destroy them in one fell swoop.

Emperor Friedrich IV of the Galactic Empire has suddenly passed away without naming a successor. Edwin Josef, the son of the late prince and the emperor's only surviving direct descendant, is only five years old. The Braunschweig and Littenheim families, into which the emperor's daughters had married, begin scheming to install their respective daughters as the new empress. Thus begins the battle for the throne between the families who serve as guardians to the emperor's three grandchildren. Reinhard has not sided with any of them yet, so a certain influential power seeks to take advantage of his military strength.

Until the age of 16, Yang Wen-li spent most of his life on an interplanatary merchant spaceship with his father, who was a trader. After his father's death, Yang entered the Free Planets Fleet Academy to study war history. There, he met Jean, who would become his best friend, and his childhood friend Jessica, a music school student

The Free Planets Alliance Navy Expeditionary Fleet encounters a grave shortage of food during its advance into Imperial territory. The 5th Fleet commander, Admiral Bewcock, conveys Yang's proposed escape plan to Supreme Commander Lobos, but Lobos fails to comprehend the situation and won't allow them to flee. Meanwhile, Reinhard has already given orders to Kircheis to strike the Alliance Navy's supply convoy. The Imperial Navy's counterattack has begun!

Military Police Commander Ulrich Kesler informs Reinhard that Count Alfred von Landsberg and Leopold Schumacher, two former members of the now-dissolved Lippstadt Nobles Coalition that fought against Reinhard during the Civil War, have reportedly infiltrated the Imperial capital of Odin. Unsure of their true intentions, Reinhard first asks Hilde to assure Annerose's safety, then summons Fezzani High Commissioner Boltik. It's June of the 489th year of the Imperial Calendar...

After defeating Legrange at the Doria Starzone, Yang's fleet heads to the capital planet Heinessen, which has been taken over by the National Salvation Military Council. Though the council's chairman, Greenhill, understands the severity of the situation, he still believes there's no way Yang's fleet can even penetrate Heinessen's gravitational field because of its specialized defense system, Artemis's Necklace. But Yang had a plan to disable Artemis's Necklace...

The Empire moves forward with its experiments to warp Geiersburg Fortress through space to attack Iserlohn Fortress. Reinhard and several of his subordinates watch anxiously from the safety of his flagship as the countdown begins. Amidst the tension, some of Reinhard's most trusted men discuss how he has changed since Kircheis died a year ago.

Count Landsberg's family had loyally served the Goldenbaum dynasty for five generations. His ancestors were even involved in the construction of a labyrinthic system of tunnels beneath the Neue Sanssouci Palace, devised to provide a safe escape for the Emperor in case of an emergency. Now this underground maze will prove instrumental in rescuing the Emperor from the usurper.