Nina Arimura, a high schooler and assistant to the Inaba Detective Bureau, recently heard a rumor that’s been getting passed among her classmates: There's a nearby mansion in which a ghoul is said to reside; a few have entered the mansion, only to never be seen again. Soon after, Arimura discovers some classmates trying to enter the mansion, so out of concern for their safety, she follows after them. Soon after, Inaba gets a call from Nina asking for help, so it is up to Detective Sogo Inaba to investigate this abandoned, haunted home all on his own...