Plot summary
While researching church history in Viborg, Denmark, in particular the events of the reformation, the narrator's cousin stays in a local inn, opting to stay in room Number 12. Once in his room, he notices that the space seems to grow smaller and his furniture sometimes vanishes.
He hears dancing in the room next door, which he notices from its door marking is Number 13, however upon discussing the matter with the inn-keep, he learns that there is no such room number in the building, as it is considered bad luck.
The narrator asks the inn-keep to visit his room at night. While talking, the protagonist and the inn-keep hear ominous singing in the room next door. They check Number 14, but learn that its occupant thought it was them. They then discover the door to Number 13 which the narrator had seen earlier. A clawed hand attacks them, and they attempt to break down the door but break through the plaster wall. The occupants of 12 and 14 spend the night in a double bedded room.
The narrator meets his cousin a few months later, and relates the tale to him.