Hermann von Luneberg and Reinhard von Müsel prepare for the ground assault on the Free Planets Alliance rear support base at Van-Fleet 4-2. Reinhard, who is assigned as sub-commander for this operation, is frustrated at being under the command of Luneberg despite both of them having the same rank. He is further infuriated when he receives an offer from Luneberg to work under him in the future. Meanwhile, Walter von Schönkopf, now the interim regimental commander of the Rosen Ritter, is facing numerous disadvantages in the organisation of the Alliance defence against the incoming Imperial assault, including inferior weaponry, inadequate supplies, a substantial numerical disadvantage and a lack of coordination between the Rosen Ritter and other Alliance ground-based troops. His plan is therefore to hold the line long enough for fleet reinforcements to arrive. On 6 April 794 UC, both sides finally clash with each other.
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.
