A group of high school students visit the inside of a mountain on an agricultural trip. While staying at a farmer's home, they learn the rural life. However, the village doesn't exist...? A shudder runs down everyone's spine as a lot of inexplicable events happen in the village, that now restricts entry. What are the high schoolers fate?

Reki Asubino possesses a cursed mark on his hand. Because of it, neighbors and classmates avoid him; his parents have left him as well. Reki may be the only person left inside the Devil's Mansion... but he's not alone. He has a lot of servants in his house… however, they're just not human. He was given as many presents as he would please, but what he really wants is a human companion. One day, he finally gets what he had always wanted inside a box, literally. Though Reki didn't only get a human, but also a caring teacher... and a dear friend... or did he?