King of Conquerors Iskandar's Relic was stolen from Lord El-Melloi II's possession. An invitation from Rail Zeppelin, the train said to have dealings of Mystic Eyes, was left in its place. Lord El-Melloi II, with Gray and Caules in tow, head towards Rail Zeppelin. Various faces have gathered at the train, such as Hishiri Adashino from Policies, Yvette from the El-Melloi Class, Olga-Marie Arsimilat Animusphere who is the daughter of the Lord of Astromancy, and even Karabo Frampton from the Holy Church. The train departs, together with the various agendas of the passengers...

An incident occurs where Trisha Fellows is murdered by someone aboard the Rail Zeppelin. Lord El-Melloi II undertakes the investigation for the case, but Olga-Marie has doubts about his way of life as it is far from how a Mage should act. Meanwhile, Shishigou and Luvia, under Reines' orders, are conducting their own investigation. The Mystic Eyes Collection Train begins its procession once again, and a mysterious figure appears before Lord El-Melloi II and Gray. The assailant who descends upon the pair with overwhelming power is the materialization of a Heroic Spirit engraved into human history... A Servant.

While giving the gravely wounded Lord El-Melloi II an arduous treatment, Gray and the others harbor doubts about an existence of a Servant whose Master is nowhere to be seen. Shishigou and Luvia are continuing their investigation in London where they visit Jean-Mario Supinerra and inquire about a serial murder that took place seven years ago. The respite was momentary as the course of the Rail Zeppelin has been altered, and the train plunges into the Forest of Dead Apostles, the Child of Einnashe. Gray, worried about the weakened Lord El-Melloi, decides to assist Karabo's group that is acting to resume the train's progress. Furthermore, Melvin, who has arrived at the Mystic Eyes Collection Train after hearing of rumors, joins the entourage. Olga Marie, barricading her lonely self after refusing to help Gray, finds a "certain something" in her own room.

Gray and the Servant Hephaestion clash within the Child of Einnashe. However, they are engulfed in an avalanche, inevitably forcing a cease-fire. While they temporarily sheathe their weapons, they speak to each other about their ideologies about the relationship between Masters and Servants. Shishigou and Luvia find out that Trisha was investigating about the serial murders from seven years ago and about the Holy Grail War, and see the link between her and the Rail Zeppelin. As various speculations intertwine, Adashino begins to disclose her own deductions in place of Lord El-Melloi II aboard the Mystic Eyes Collection Train...

As Adashino's deductions are playing out, Lord El-Melloi II makes his comeback. He sees a clue to the identity of the true perpetrator of Trisha's murder from Gray's testimony, and requests Melvin to delay the Mystic Eyes Auction from starting. His objective is to seek assistance from Olga Marie, and grasp conclusive evidence to overturn Adashino's deductions. Meanwhile, in London, Shishigou gathers up Flat and Svin in order to proceed with certain preparations. As each of them reflect upon their own ideas, the fated Mystic Eyes Auction finally begins.

Caules Forvedge is suddenly apprehended as the perpetrator. As Lord El-Melloi II causes the Mystic Eyes Auction to pause while disclosing his deductions, Reines, who is supposedly still in London, rushes over to his side. Thus, Lord El-Melloi II points out the name of the true perpetrator.

Several days after the incident on the Mystic Eyes Collection Train, there was a solemn ritual at Modern Magecraft Theories for Svin's ascendance to the rank of Pride. Lord El-Melloi II looked upon the ritual full of emotion as this ascendance to Pride was while his student was still in his teens. Meanwhile, Gray could not shake off the uneasiness that Lord El-Melloi II would depart for distant lands to participate in the Holy Grail War. While in thought, she bumps into Melvin in the streets bustling with the approach of Christmas.