In the whole world there lay a mythical creatures which have their own ecosystem and can’t be considered part of the food chain. They also have supernatural powers and live together with humans. Ferry is one of the professional investigator, who researches the connection between the creatures and humans and is called a Genjuu Chousain (Mythical Beast Investigator). The story starts when a flying reptilian dragon (Wyvern) is attacking a village, and a Girl dispatch on the quest to research and investigate Wyvern and other mythical creatures.

After dying, Sena Kaito was reborn in another world and confronted with a peerless beauty, Elisabeth, who had appeared before his eyes. Introducing herself as "Torturchen," she commanded Kaito to become her servant, but he refused on the spot. When Elisabeth presented Kaito with the choice of either torture or butler, he immediately submitted and began to serve at Elisabeth's side, to accompany her until she completed her mission.

─Would you like me to save you?─

Under a blooming cherry blossom, Odagiri Tsutomu encounters a beautiful girl dressed in Gothic Lolita fashion and holding a red paper umbrella. She is Mayuzumi Azaka, head of the Mayuzumi psychic investigation agency. Surrounded by a strong chocolate aroma, Odagiri became her assistant and got involved in several supernatural cases.

A cruel and painful, ugly and beautiful mysterious fantasy is about to begin.