Gyakuten Sekai no Denchi Shoujo  

Rumble Garanndoll, 逆転世界ノ電池少女, Reversal World's Battery Girl, Turnabout World's Battery Girl, สาวน้อยวัยใส พิชิตชัยในโลกเผด็จการ, Батарейка из обратного мира

In 2019, just before the dawn of a new era, a rift to another dimension appeared in the sky, unveiling an alternate world called "Shinkoku Nippon." This parallel universe retained its former militaristic mindset and maintained the Eternal Showa era. The military from this alternative world invaded Japan with giant humanoid robots known as "Garann" and their gas weapons "Genmu," which rendered our modern weapons ineffective. As a result, "Shinkoku Nippon" seized control of the Japanese government and achieved de facto conquest over Japan. The new era, "Reiwa," has now begun for Japan.