Walter von Schönkopf, worried that his superior Otto Frank von Wahnschaffe, the regimental commander of the Rosen Ritter who is leading the Alliance reconnaissance mission, might have encountered Imperial forces, sets off with his trusted subordinates to find him. Along the way, they discover that Hermann von Luneberg, who is revealed to be the former regimental commander of the Rosen Ritter, is commanding Imperial troops on Van-Fleet 4-2. Although they manage to rendezvous with Wahnschaffe, they are soon ambushed by Luneberg's troops and are only able to retreat after suffering considerable losses, including the life of Wahnschaffe. After returning to base, Schönkopf requests command authority from the base commander so that he can organise the defence against the expected Imperial full-scale assault on the base. He also recommends the commander to call for reinforcements from the Alliance fleets in Van-Fleet Starzone, which is then picked up by the 5th Fleet. Its commander, Alexandre Bewcock, decides to provide full assistance.
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.
