An affluent white-collar worker receives a mysterious invitation: "Would you like to know what life is about?" "Would you like to live your life fully?" It is sent into the unpredictable space of the Lord God, and future human beings will invite and challenge the present world, and the different challenges that humans face during the era of great universe development will be simulated as copies as well. The "copies" will guide the selected people to overcome many traps, meet life-and-death comrades, and become leaders. All of this is in the interest of human evolution, survival, and infinite futures!

Hayase Nagatoro and Naoto Hachiouji have grown closer: the girl spends more time than ever in the art club room with her senpai. Although he is always on edge, Naoto no longer seems to mind Nagatoro's presence. Time and again, Naoto demonstrates his hidden, cool demeanor, and Nagatoro displays her possessive tendencies. However, they still can not seem to completely close the distance between them. It is clear to everyone else that the pair have feelings for each other. For Nagatoro, there is nothing more entertaining than toying with Naoto. But as the girl shows no plans to stop teasing her senpai, it is only a matter of time before they realize how they truly feel.

Human civilization no longer revolves around fire, but is instead now driven by fear of it. Repeated wars have changed human biology, and people now spontaneously combust when they get close to natural flame. However, a new source of energy prevents society from complete collapse: a stone-shaped material used to produce light and steam lies within the bodies of monsters that infest numerous forests. Those tasked with collecting this precious resource are called fire hunters. Touko, a young village girl, is saved from a forest monster by a fire hunter who perishes during his heroic action. After the hunter's dog, Kanata, heals from his own injury, the girl's family sends her to the capital in order to return Kanata and the hunter's fire sickle to his relatives. Elsewhere, the fire hunter's son, Koushi, and his sister are adopted by a wealthy family. Koushi learns some troubling facts related to the country's ruling royal family. He conducts secret research on a special fire stone found by his late father, kickstarting a race against time between the country's leaders and those trying to save mankind from its ultimate demise.

Second part of Dungeon ni Deai wo Motomeru no wa Machigatteiru Darou ka IV.