Despite admitting to Siegfried Kircheis his awareness of Christopher von Basel's role as the leader of a thyoxin trafficking organisation, Michael von Keyserling refuses to testify against him. Kircheis then visits Johanna von Basel, who reveals that she was already aware of her husband's wrongdoings and was in fact the mysterious informant who tipped the police of Kreuznach III about the imminent arrival of the leader of the thyoxin trafficking organisation. However, she does not plan to testify against him either and was actually hoping her husband to apologise to Keyserling for all his wrongdoings, which backfired when the former tried to silence the latter instead in the previous day. Feeling desperate at the lack of progress, Superintendent Hoffmann asks Kircheis to confront Christopher von Basel directly. Kircheis does so and succeeds in tricking Basel into admitting his guilt. However, before the police could arrest him, he calls his wife to burn away potentially incriminating documents who, out of her love for him, complies. While Kircheis hesitates to incapacitate her, Keyserling suddenly appears and shoots his once-beloved, ending the struggle. The next day, with the case concluded, Kircheis meets up with Reinhard von Müsel in the spaceport of Krueznach III and continues their short vacation.
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.
