After his meeting with Superintendent Hoffmann, Siegfried Kircheis returns to the hotel he is staying in, only to find an invitation by Michael von Keyserling to a dinner in a restaurant as a gesture of thanks for saving his life. Kircheis decides to take up the invitation. During the dinner, he learns a little about Keyserling's past and that Keyserling is planning to meet up with his old friends, whom he says will not arrive till the next day. After the dinner, Kircheis meets up with Hoffmann again, who reveals to him that Keyserling's would-be assailant used to be a subordinate of his when he was in active service. While it is highly probable that Keyserling himself would not remember a low-ranking subordinate, their links with each other are too good to be a coincidence. Following that, Kircheis returns to the hotel and retires for the day. During the same night, he is almost suffocated to death by someone who placed huge quantities of dry ice in the air-conditioning system of his room. Hoffmann, who arrives almost as quickly as Kircheis awakes, begins to suspect Keyserling for the act. Kircheis however is not really convinced. He then learns from Hoffmann that Keyserling's old friends have already arrived in Kreuznach III. However, when he meets Keyserling during breakfast in the next morning, he neither seems aware of Kircheis' near-death experience nor the fact that his old friends have already arrived.
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.
