Yahiro and the gang head to Kyoto hoping to figure out how to turn the Japanese populace back into humans. When Galerie Berith’s armored train stops in Nagoya, the Chinese Federal Army, the current occupant of the former Nagoya Station, demands that the Galerie surrender Vanagloria’s Regalia in exchange for safe passage. By that time, the powerful Relict has fused with Ayaho, and handing over one of Iroha’s siblings is the last thing they’d do. Can they protect her, negotiate their way out of the situation, and defend against a herd of Moujuu all at once?

Bound by his contract with Galerie Berith to hunt dragons, Yahiro heads to the Fortress City of Yokohama, which is under the control of the Guild—a neutral organization that acts as an intermediary between private military companies. There, he finds the swamp dragon medium Nina Himekawa and her Lazarus, Hisaki Minato, waiting for him. Then, Waon Iroha is invited to collab with a streamer backed by a European enterprise named Gibeah. Although she is initially overjoyed at this news, things quickly become complicated when she realizes the corporation is connected to the Japanese Council for Independence, who mean to take their country back...by any means necessary.

When Iroha’s channel surpasses a million views overnight, Yahiro and the others know the reason can’t be anything good. As it turns out, a sleuthstreamer called Yamadou has exposed her as a dragon medium on his channel, and now the whole world is watching Iroha’s every move! Before Yahiro and Galerie Berith can do anything to retaliate, the Guild detains Yahiro...as a suspect for a rash of murders?! While Yahiro is away, the Galerie’s Japanese branch comes under attack by a foe with an old grudge. And with more Lazaruses appearing to shake things up, Iroha and her siblings may be in more danger than ever.

Four years ago, a dragon filled the sky, the nation of Japan fell, and Japanese people around the world were wiped out. Yahiro, a survivor of the tragic event, works as a salvager who obtains Japanese artwork and artifacts for foreign buyers. Not many are willing or able to brave the ruins, which are crawling with monstrous beasts called Moujuu. But Yahiro’s the best man for the task. After all, thanks to his regenerative abilities, he can’t really die. He’s approached about a job to search for the Kushinada, which is capable of controlling the Moujuu, but it will require delving into the most dangerous parts of the city. This is the story of a dragon girl and a dragon slayer.

Yahiro and the others journey to Kyoto aboard Galerie Berith's armored train. There, they hope to discover the truth about Japanese people having transformed into moujuu. The train screeches to a halt when soldiers stationed at Nagoya demand a toll-the Regalia: a crimson gem that is...fusing with Ayaho?! There's no way Yahiro or Iroha will hand her over, but how will they keep everyone else safe and escape a barrage of attacks from soldiers and moujuu?

As the century-long war between the Empire and the Nebulis Sovereignty rages on, the star-crossed lovers from enemy nations continue to miss their opportunity for a rematch. But when Iska and Aliceliese are both given orders from their respective superiors to track down the source of this ancient grudge, they might just have a chance to battle it out.