"It wasn't me who was the strongest in another world, but my sister?!"
As a result of an accident in the real world, Asahi Ikusaba is transported to another world. He tries to enjoy the different world he imagined, but his abilities prove to be the weakest. Just as he's about to be attacked by a vicious monster, Asahi's doting elder sister Mayu comes into his rescue and saves him.
Chasing after Asahi's love, Mayu too ended up in the same world as him, with the strongest of abilities and cheat skills. The fantasy tale of the strongest elder sister with a brother complex and the younger brother with the weakest skills begins.
The story is set in an alternate world called Yamauchi, ruled by the Yatagarasu clan, who are able to transform between human and crow forms. Yukiya, a beautiful and eccentric Yatagarasu boy, is chosen to serve the young prince. While encountering various events in the conspiracy-filled imperial court, he forms a strange master-servant relationship with the young prince.
The everyday life of Nakano, a salaryman working for an exploitative company, is suddenly intruded upon by the fox, Senko-san (800-year-old little girl). Whether it be cooking, cleaning, or special service(?)... she'll heal his exhaustion with her tender "care."
