The case is the story of a friend of the game's scenario writer, Masao Ikurumi.
A freelance writer "Renji Mirokuin", who is a writer of occult articles for a living, is assigned to cover an urban legend called "Red Elevator".
The story begins when Renji Mirokuin, a freelance writer who writes occult articles for a living, heads to a condominium where the urban legend "Red Elevator" is said to have originated.

When the elevator is called on the first floor of the haunted apartment building, "BOX" slowly, slowly comes down from the rooftop, which is supposed to be off-limits to visitors.
When the elevator arrives at the first floor, it opens its mouth to reveal a bright red interior...

A strange dwelling full of empty rooms. The residents keep their mouths shut. The "incident eight years ago" is said to be cursed if it is told.
Mirokuin, who pursues the truth hidden in the urban legend, confronts the horror that night.

[From Steam]