The story concerns a young man named Mr. Thomson who is the only guest at a small seaside inn. On a sunny afternoon, Thomson decides to explore the inn's other bedrooms. He finds that only one of those rooms has a locked door. Inside the room, he finds a bed with a completely covered human form on it.
The unnamed narrator begins his story by saying that the moldy old sheets and blankets on beds in some long-abandoned bedrooms can be seen to move because there are rats beneath them. He then goes on to say that an acquaintance of his, Mr. Thomson, once saw the bedclothes in a bedroom which had not had a human occupant for many years move for a different reason.
In about the year 1846, Mr. Thomson, a student at Cambridge University, spends a spring vacation on the Suffolk coast. He stays at the small inn owned by Mr. and Mrs. Betts. He is the only guest who is staying at the inn, although many of the local people go there to drink in the evening.
On a walk one day, Mr. Thomson notices a square block of white stone with a square hole in the top. That evening, he talks about it at the inn. He says that he believes there was once a marker in the stone that was intended to guide ships. Mr. Betts says that there was once something in the stone that could be seen from the sea but it fell to pieces long ago. One of the inn's customers says that fishermen destroyed it because they believed it brought bad luck. There is a period of silence before Mr. Betts changes the subject.
One sunny afternoon, while Mr. and Mrs. Betts and most of the rest of the inn's staff are out, Thomson decides to examine the other three bedrooms on his floor. He finds that the doors of two of those rooms are unlocked. Those rooms are unremarkable and not quite as nice as his own. The door to the third room is locked. The key to Thomson's own room does not fit the third room's lock but the key to one of the other empty rooms does. There is nothing in the room except for a bed. Beneath the blanket is the shape of a person. The head is covered, as if the person were dead, but the form is moving. Thomson approaches the bed to find out if he can hear the sound of breathing. He cannot. He leaves and locks the door. He then hears the sound of footsteps coming from inside the room. Thomson runs back to his own bedroom and locks the door. He thinks about leaving the inn immediately. He then remembers that he told Mr. and Mrs. Betts that he planned to stay for another week and that his sudden departure would seem strange. He reasons that, since Mr. and Mrs. Betts share a house with the occupant of the room and are not afraid of it, he need not be afraid of it either.
Thomson stays for another week and makes no attempt to find out anything about the third empty bedroom from any of the local people. To satisfy his curiosity, however, he comes up with a plan to inspect the room again before he leaves the inn. When a carriage arrives to take Thomson to the train station, he says that he would like to check his room to see if he left anything behind. He unlocks the door of the third bedroom and sees a scarecrow propped up on the bed. Thomson laughs at himself for having mistaken a scarecrow for a ghost. He then sees that the scarecrow has bony feet and a chain around its neck. The scarecrow gets up and begins moving forwards slowly and stiffly. Thomson runs downstairs and faints.
When Thomson comes round, Mr. and Mrs. Betts explain that, when they bought the inn, the previous owners told them to keep a bed in that room and to keep its door locked. They have never seen the ghost but know that it is the spirit of a former landlord of the inn who was also a highwayman. The highwayman was hanged on a gallows that once stood in the white square stone block that Thomson saw. It is true that local fishermen destroyed the gallows long ago because they thought it brought bad luck. So as not to damage the reputation of the inn, Thomson promises to say nothing about his ghostly experience. He keeps that promise for a long time.
Many years later, Thomson stays at the narrator's father's house. The narrator leads Thomson to the guest bedroom. Thomson insists on opening the bedroom door himself and on standing in the doorway to inspect the room before entering it. He later explains to the narrator why he is cautious about entering any unfamiliar bedroom.
A short film adaptation of "Rats", directed by Stephen Gray with an amateur cast headed by Craig Malpass and Theresa Roche, was released in 2010. The film can be viewed on the website of its director in the external link below.
A 15-minute radio play based on "Rats", starring Mark Gatiss as M.R. James, was first broadcast on BBC Radio 4 in the United Kingdom on December 21, 2018 as the fifth and final episode of the mini-series The Haunting of M.R. James.
- The narrator says that he does not know exactly when the story takes place but believes that it was in what Orlando Whistlecraft described as the "Charming Year". Orlando Whistlecraft (1810-1893) was an early British meteorologist who wrote a book called The Magnificent and Notably Hot Summer of 1846.
- The other episodes of The Haunting of M.R. James are based on "The Mezzotint", "Casting the Runes", "The Stalls of Barchester Cathedral" and "A Warning to the Curious"
- Text of M.R. James' "Rats" on Faded Page.com. The site is hosted in Canada where the story is in the public domain. It is still under copyright in the United States.
- 2010 amateur short film Rats on the website of its director Stephen Gray.