- Mr. Brook, the head of a music department, has hired Madame Zilensky—a well-regarded composer and teacher—to join the faculty. Because of this, Mr. Brook has arranged that she stay near campus, in a house next to the building where he lives.
- No one in the town has ever met Madame Zilensky, although Mr. Brook has seen pictures of her, and once wrote to her in order to authenticate a document.
- After she was hired, they wrote more regularly, and she talked about people and things Mr. Brook could not have known about… which totally confused him.
- Mr. Brook is quiet, and keeps to himself. He once escaped a departmental vacation to Salzburg by booking a trip to Peru instead.
- Despite this, he's totally entertained by the eccentric and ridiculous.
- Just before the fall semester starts, Mr. Brook meets the strange, disheveled, and elegant Madame Zilensky at the train station. She's with her three boys and an old servant woman. All of their luggage has been accidentally left at another train station and all they have with them is a couple boxes of manuscripts.
- Just as Mr. Brook has settled, Madame Zilensky climbs over him, realizing she has lost track of her "tick-tick-tick"… which he eventually understands to mean "metronome." He says he'll get her another, and doesn't understand why this—of all of the forgotten luggage—is the thing Madame Zilensky is obsessing over.
- The Zilensky family moves into the house beside Mr. Brooks and everything seems quiet, particularly the children Sigmund, Boris, and Sammy.
- The Zilenskys make Mr. Brook "uneasy," but he's not sure why. Eventually he realizes it's their strange quirks: the way they won't walk across a rug and the way Madame Zilensky leaves the house empty.
- Madame Zilensky turns out to be a passionate, effective teacher, and works manically on her twelfth symphony, never seeming to sleep.
- Mr. Brook's uneasiness gets worse as the autumn goes on. After an otherwise enjoyable lunch listening to Madame Zilensky talk about an African safari she took, she stopped at his office to inquire after the metronome—whether he thought she had left it with "that French."
- Mr. Brook is confused, and she says he is her ex-husband.
- The father of the children? asks Mr. Brook. She says he is Sammy's father. Despite himself, he asks after the father of the other two. She says that Boris is the son of a Polish piccolo player, and trails off. The other, she says, "was a fellow countryman."
- It bothers Mr. Brook that all of the children look alike, and none like Madame Zilensky.
- Madame Zilensky resolves yes, she must have left it with the French, and leaves.
- Everything in the department is going well, no scandals but his "nagging apprehension" about Madame Zilensky.
- He can't figure out why he's so fond of her, nor why he finds her so suspicious. She is completely quiet for some days and a total chatterbox on others, and when she does speak, everything — no matter what it is — seems glamorous and alien.
- It's suddenly clear to Mr. Brook, as he sits in front of a fire in his living room: The King of Finland. Once, Madame Zilensky had told him how she had stood in front of a bakery when the King of Finland passed by on a sled. There was no King of Finland, he thinks: she's a pathological liar.
- He's frustrated but excited about this realization. He's eager to study Madame Zilensky more carefully and to figure out why she lies as she does.
- By midnight, drowsy with brandy, Mr. Brook thinks he has figured it out: she is a hardworking woman with a boring life. The thought makes him feel kindly about her.
- By the time he's brushing his teeth, he realizes that a boring life doesn't quite explain anything: where did the children come from, he wonders.
- It's late, and he sees her lights are still on. He goes to sleep, trying to figure out what to do about all of this.
- In the morning, Madame Zilensky passes by Mr. Brook's office, telling him how wonderful her night's sleep was.
- Mr. Brook asks her to sit down. He mentions the King of Finland, and she retells the story, but Mr. Brook stops her, insisting that there is no King of Finland and that the story must be a lie.
- Madame Zilensky looks astonished, and then goes through the facts: she is a Finn, she was a motorcycle messenger in the war… but Mr. Brook attempts to proceed.
- Her face stops him. He feels he terrible, like a murderer, and he's overwhelmed by a strange love. He finds himself asking, with sincerity, whether the King of Finland was nice.
- Later, looking out his office, he spots a neighbor's dog walking down the street and it strikes him as strange, though he's not sure why.
- Then he realizes that the dog is running backwards. (Yup.)
- He resumes his work.