The Woman Next Door is the first chapter of Mimi's Ghost Stories.
This story introduces Mimi, the protagonist of the volume. It is preceded by a very short prologue titled "The Electric Pole", in which Mimi is driving home with her friends when they see an old woman's ghost on top of a telephone pole. They are so startled that they crash the car, but the ghost vanishes.
Mimi confronts a man living on the floor above her, who refuses to turn down his music. He says he will only turn it down if the next door neighbor complains. Mimi thought the room was empty, but the man says he has heard the door opening and closing so someone must live there. At this point, the tenant comes out and leaves: a woman who dresses in black from head to foot and whose face is completely covered. Another neighbor tells Mimi that two or three women live in the room, all have very different figures but dress in the same black outfit and cover their faces.
Eventually, the upstairs neighbors stops making noise. Mimi is satisfied but one day she finds him sitting outside the building. He tells her he is terrified of the women next door to him, who never make any noise even though they seem to be at home all day and the walls are very thin. As if on cue, one of the women appears and goes up the steps into the building. That night, Mimi hears him screaming; and he moves out the following day.
Despite the creepy women, Mimi moves into the man's vacated room as she figures it will be quieter than her own. One of the women trips over Mimi's furniture in the hallway and drops her groceries. Mimi tries to help her but discovers the woman's arm is a single metal rod. Mimi talks to her friends, who think that maybe it's a prosthetic, but Mimi isn't convinced. She eventually agrees with them that maybe she imagined it.
Alone at home, Mimi realizes that just like the guy who moved out, she can hear absolutely nothing next door. She discovers a hole that was recently made in the wall, probably by him. She looks through it and sees the woman she met earlier, revealing she is a robot taking the screws out of her metal arms which allows her to extend her arms to a great length. The woman then looks straight through the wall at Mimi (wearing sunglasses.) The woman's arm comes through the hole and begins to destroy Mimi's room. Mimi realizes there was only ever one woman; she just looked different since she could expand and contract her body.
Mimi blocks the hole with a bookcase but then the woman appears from outside of Mimi's window, now with freakishly elongated limbs. She breaks in through the window and begins to attack Mimi, losing her sunglasses in the process, but Mimi loses consciousness before she can see what's beneath. Afterwards, the woman carries on next door as if nothing ever happened. Mimi makes plans to move somewhere else.