Gate – Jieitai Kanochi Nite, Kaku Tatakaeri

A gate appears in Tokyo’s Ginza district sometime in the 21st century.

From the gate pours out monsters, knights from middle-age Europe,

and other fantasy-like beings, and they kill many of the citizens of Tokyo.

This event is known as the Ginza Incident.
The government sends a small group of soldiers

from the Japanese Self-Defense Forces to the alternate

world beyond the gate. Led by otaku soldier Yōji,

they find that the villages in the world are being attacked by a dragon.

An elf girl who is a survivor from the dragon’s rampage joins

the group in their travels across the dangerous new world.