Amane Todoroki is a young girl who is straightforward but also unthinking. She will try her very best in everything and say, "I don't know how to answer you if you ask me whether this can be done. I just believe it can. If not, then nothing will get started!" She easily gets stuck in her thinking, but she can also get easily moved at something small and start crying.

Enma is a character created by the genius manga artist Go Nagai. Now, the popular character makes his appearance in an alluring Japanese horror anime for adults. It's a hair-raising erotic suspense in which Enma takes on complicated and gruesome incidents caused by demons who lurk in the darkness. But humans have lit up the darkness of the night with neon lights and turned their world into one that never sleeps, so demons now lurk in the "darkness of the human heart." Unfulfilled hearts, suppressed hearts, despair,...such darkness of the heart is the place they lurk. Enma is the Demon Prince of the Underworld, a demon "Born of Fire." His mission is to take back or destroy demons that have escaped to the human world from the Underworld. Along with his partner, Princess Yukihime, "Born of Ice," and the monster, Kapaeru, Enma sets up "Enma's Detective Agency." Tonight, like any other night, they will roam the sleepless city. Horrific incidents that could not possibly be human acts occur one after another. The stench of evil lingers at the scene... Enma's fire rips through the darkness!

The story centers on Nayu, a middle school girl who shocks her schoolmates on the first day of school by wearing black lace panties. She likes this kind of underwear, and she tries to "spread the word on the merits of [these kinds of] underwear" via an underwear club with her schoolmates, who are worried about their bodies' development and which underwear to choose.