Gyakuten Sekai no Denchi Shoujo

In 2019, Japan was on the brink of a new era when a rift opened in the sky. It revealed an alternate world called "Shinkoku Nippon", and the sky and earth were upside down. This parallel world had kept their militarism, and with giant robots called "Garann" and gas weapons called "Genmu", they overwhelmed modern weaponry.

The military quickly conquered Japan, and the new era known as "Reiwa" began. Despite the situation, Japan has bravely moved forward with hope for a better future.