As conflict rages at the peace conference between Altar and Dryfe, another battle entirely breaks out on the city streets. Ideologies intersect as those seeking the truth clash with each other, while a treasure-seeker makes her own desperate play. A grand battle, one that may well begin to unravel the mysteries weaved into the world, is about to unfold... What exactly are the Control AIs? What is the nature of the Arch Sage? And, perhaps most urgent of all... How might the people within Infinite Dendrogram avoid the ultimate Game Over?

In a world of infinite possibilities, how would you choose to live?

The City of Duels remains under siege, and Gideon's peace has been shattered by the malicious machinations of Giga Professor Franklin! As Ray and Rook draw ever closer to a fateful showdown with a former friend, Marie moves in hot pursuit of the dastardly fiend, only to be stopped in her tracks by Veldorbell, the King of Orchestras. Pushed to the brink, she has no choice but to play her full hand and reveal her biggest trump card... But what kind of catastrophic consequences will this artistic clash have for the city at large?

The City of Duels is Heating Up! A challenger from Huang He comes to duel Figaro, the local legend. As luck would have it, Ray just so happens to have a front-row seat! Both of these Masters wield powerful Superior Embryos and have no intention of losing. Who will be left standing at the end of this ferocious encounter? As the duel comes to a close, a shadow looms over the city of Gideon. Mr. Franklin, the Giga Professor from the Dryfe Imperium, makes his terrifying debut! The sadistic scientist sets his sights on throwing the city into utter chaos. Unfortunately for him, Ray, Marie, and Rook aren't about to go down without a fight! Outmatched, outnumbered, and outsmarted, the knights and Masters of the Kingdom of Altar swiftly prepare to retaliate. Will their fighting spirit be enough to defeat this mastermind?

An AI looks into the past, at an event long before Ray Starling set foot in the world of Infinite Dendrogram. The unstoppable Tri-Zenith Dragon emerges from the mountains. It is a bringer of death, wielding a miasma of desolation in its wake. The citizens of Altar can do nothing but watch as doom descends upon them. However... There are three who may be up to the challenge. Three Masters who, if they managed to work as one, could stop the imminent desolation of the land they call home. But with so much glory to gain, what could they stand to lose?

"First published in Japan in 2018 by Hobby Japan, Tokyo."--Colophon.

Ray finds himself kidnapped by The Lunar Society, and is approached by their spiritual leader and the last Superior of the kingdom -- High Priestess, Tsukuyo Fuso, who begins to unfurl her nefarious scheme.