30 years before the plot began, a space earthquake erupted, elves appeared, and 150 million people died. Pen @ fun @ pavilion wWw. ｂｉｑUｇE。 ｉｎｆｏ

Six months after the Great Eurasian Air Disaster, the area from southern Tokyo to northern Kanagawa Prefecture turned into a round scorched earth as if it had been wiped with an eraser. After that, a new city was established, Tiangong City, and redeveloped after the disaster.

In the first twenty-five years of the blank period, underground shelters were widely spread, and the ability to detect space earthquake disasters meant that DEM was established, and Japanese AST was also established.

Five years ago, a space earthquake loomed in Tiangong City, and a large number of space earthquakes gathered in Japan. (Note that this point is more important from the amount of information in the original text, presumably foreshadowing by the author.) ）

Five years ago, Ryota Natsukawa, the president of DEM Society, and his wife, Reiko Natsukawa, captured Tokizaki Crazy and wanted to obtain the power of the elf, and extracted the power of the doppelganger and poured it into his ten-year-old daughter.

The test succeeded and failed, and a fire broke out in Nanjia Town, Tiangong City, the test site, which was caused by an accident. Natsukawa Yuki lost his memory, and at the same time, Irichi Origami also lost his parents due to this accident, which was actually the result of the intervention of the elves.

In order to protect her brother from this fire, Jeanri obtained the power of the elves from the (mosaic) elves. The organization to which Kotori belonged also began to be formally prepared and established.

Tomoki Natsukawa and Irichi Origami enter the orphanage at the same time and establish a deep relationship. A month later, Yuki Natsukawa returned to Natsukawa's house as an adoptee.

Three months later, Reiko Natsukawa wanted to test the results of the power of the elves. Unexpectedly, Yuki's elven power went berserk, Reiko's time and other people's time were absorbed by Yuki, and Ryota Natsukawa was almost sucked dry and breathless. It seems to be an accident, but it is actually the result of the intervention of the elves.

Ryota Natsukawa was revived during a secret operation by the DEM Society, but was incapacitated. Westcott seized the opportunity to seize power, and Ryota Natsukawa's henchmen were all killed in assassination. (This is something that Takemiya-sensei talked about to Tomoki.) ）

For this reason, Ryota Natsukawa asked his cousin Masaki Natsukawa to be his agent and handed over his research to Yuki, which was already a month later.

Although he is still alive, his movement is restricted, and he can't let Westcot know that he is still alive, so he hides the news that he is alive, and looks at his daughter with the help of softness, and usually receives treatment at the dem society hospital belonging to Tiangong City, and he can delay his life for a day. (Mr. Takemiya said that he didn't know why the hospital belonging to the DEM in Tiangong City was particularly large)

A year before the story began, Wuhe Shidao was admitted to the metropolitan Lai Zen High School, and the plot will officially begin.

Everyone should know the plot after that.