Siegfried Kircheis returns to his hometown for a short trip to visit his parents, whom he has not met for eight years since joining the military. During his short trip, he reminisces about his childhood and unexpectedly meets up with an old acquaintance. A few days later, Kaiser Friedrich IV reveals that he is planning to award Reinhard von Müsel with a countship upon his twentieth birthday to Admiral Grimmelshausen, who concurs with the plan wholeheartedly. Within a day, news of the plan spread like wildfire throughout the Imperial Court and eventually reaches Reinhard's ears, who, in an uncharacteristic manner, looks forward to it enthusiastically. The reaction of the high nobles towards the Kaiser's plan is however one of outrage and hostility. Meanwhile, another rumour emerges in the Imperial Court, this time revolving around the background of Hermann von Luneberg.
Prequel to the original series, focusing on Reinhard and his steps up the chain of command in the Galactic Empire. Also focusing on the FPA's Yang Wen-li. A chronicle on how he earned the title "The Hero of El Facile" and his handling of assignments he received after the historic event. Spiral Labyrinth also continues with the background of Reinhard and Kircheis where the first Gaiden left off.
