Harriet attempts to figure out what her classmates are planning. She sees Sport with his tool kit and Carrie Andrews with nails in her pocket, and predicts that they are either building something or plotting to catch her and drive nails through her head. It drives her crazy to see everyone whispering together, but not saying a word to her. After school, Harriet sees everyone head off to Rachel Hennessey's house. Though she considers following them right away, habit forces her to go home and have her cake and milk first. As usual, she crashes straight into the cook on her way in, and the cook threatens to quit if it happens again.
Harriet puts on her spy clothes and sneaks over to Rachel's house. She climbs fences and sneaks through gardens until she is in the yard beside Rachel's, peering through her fence. All of her classmates are there, and they appear to be building a small house, with Sport in charge. Rachel's mother comes out to give them all homemade cake, and Harriet realizes this must be the only reason why they chose Rachel's garden. Harriet tears a page from her notebook, writes an anonymous note to Mrs. Hennessey saying that all those kids hate Rachel and are only there for her cake, then places it in the mailbox. Then she quickly runs home.
The next day at school things begin to get worse, and Harriet attempts to keep her cool. Janie throws a spitball at her. Rachel fakes tripping and dumps a big bottle of blue ink all over Harriet, covering her clothes and shoes. Miss Elson insists it is an accident and Harriet should not blame Rachel, but the kids in the class laugh behind her back, making it clear that Rachel did it on purpose. Harriet is sent home to take a bath, and after insisting to the cook that she is not sick, she sits in the tub and cries for a long time.
Harriet goes back to Rachel's to spy again the next afternoon. Rachel is telling everyone about the note her mother received, and she guesses that it was from Harriet. The children finish painting a sign, and to Harriet's horror, it reads "The Spy Catcher Club." She realizes they have made a club against her.
In school Harriet writes furiously in her notebook all day, staring every once in a while at a particular person to make them think she is writing about them, even though she is simply writing down a series of memories from her childhood. Harriet's teachers try to make her pay attention, but to no avail. One afternoon her classmates stage a parade in the park for her to see, carrying a sign that says "This parade the courtesy of the Spy Catcher Club." Harriet is furious and embarrassed, but she allows them to walk by her, then runs home before they can a second time.
At home, Harriet's mother comes to talk to her, apparently having been told to do so by her teacher Miss Elson. Her teachers are concerned that she has not been doing any schoolwork because she spends the whole day writing in her notebook. Much to Harriet's dismay, she tells her that from now on, she will only be allowed to write in her notebook outside of school hours. She frisks Harriet the next morning to make sure she does not bring her notebook to school. Miss Elson also searches her when she arrives. Harriet finds it difficult to think and do her schoolwork without her notebook's reassuring presence.
In a sour mood, Harriet secretly trips Pinky Whitehead and pinches Carrie Andrews, in both cases framing someone else or running away before anyone can blame her. She also wads up a piece of paper and throws it at Sport, then feigns innocence. Harriet runs home from school as soon as it ends to get her notebook from the cook, rushing upstairs to write without even having her cake and milk. She writes about how something is changing and she does not feel like herself anymore, then makes a list of the best way to hurt each individual person, specifically tailored to them. Marion Hawthorne, for example, would be terrified if she put a frog in her desk, and the best way to get back at Laura Peters is to cut her hair.
She enacts these plans over consecutive days at school, saying mean things to Rachel about her absent father, cutting Laura's hair, and finding a frog to put in Marion's desk. Harriet goes home and vindictively jumps up and down in the kitchen because the cook told her she must not move around a lot so as not to disturb the fragile cake baking in the oven. The cook declares in a fury that she has had it, and she quits. Harriet's mother convinces her to stay for a five dollar raise, but the cook insists something must be done about Harriet. Harriet refuses to talk to both her father and mother.
The next morning Mrs. Welsch says she is taking Harriet to see a doctor. He is a therapist named Dr. Wagner, and Harriet goes in to talk to him for a while. She is dissatisfied, because he spends most of the time answering her questions with more questions. Harriet asks about his notebook when she sees that he has one to take notes, and is annoyed that he keeps taking notes as they play a game of Monopoly. He gives her a spare notebook so she can write as well, and she writes mean things about the doctor's appearance until it is time to leave.
Harriet decides she will go to see Sport and Janie and privately try to be friendly, because they were her best friends and perhaps they are tired of being angry at her. When she gets to Janie's, Janie is so shocked to see her that she drops a test tube and gets mad at Harriet for making her do it. Janie refuses all Harriet's attempts to be nice, so she goes next to Sport's house. Sport's father has finally managed to publish his book, and Harriet, who wants to be a writer herself, asks him what it feels like to get paid for what he writes. He announces that he will use his large check to take Sport out to dinner, and offers to bring Harriet as well—Sport, however, loudly refuses to let Harriet come with them. That night Harriet has another nightmare about missing Ole Golly, and does not allow her mother to comfort her.
These chapters continue the book's principal idea of exclusion being a particularly difficult kind of pain to endure for a child. Harriet is independent, of course, but even the most independent child sometimes takes for granted the comfort and support of friendship. Now that Harriet has lost not only her beloved nurse, but her friends, isolation is suddenly something awful rather than something desirable. It is made worse by the existence of the secret "Spy Catcher" club; Harriet fancies herself a spy, and spies don't like to have secrets kept from them. Her classmates know what will make her angriest, and they capitalize on it.
In the wake of Ole Golly's departure and the notebook fiasco, Harriet's already stubborn, haughty personality gets worse before it gets better. Before this incident, Harriet's notebook had been her place to be angry and judgmental in private, letting out her unfiltered thoughts so that she would not need to speak them aloud. When Harriet's mother confiscates her notebook, she does not have this outlet, so her pent-up frustration manifests itself in vengeful, vindictive ways. Harriet is not truly a mean person, but the things she does to get back at her classmates—cutting Laura's hair, making comments about Rachel's absent father—are positively cruel, making it clear just how deeply the loss of this vital outlet of self-expression has affected her.
But the notebook is more than just a place for Harriet to take out her frustrations—it is also her security blanket, her source of comfort and familiarity when things become tough. Without its reassuring presence, she cannot concentrate in school, cannot focus on her work or think clearly. She has come to rely on this notebook so much that she is now entirely dependent on it, and not having it is like losing part of her identity. In a span of a few days, Harriet's life has turned upside down, and she is being challenged to cope: so far, she has not been able to.
In a time of emotional and social turmoil such as this, Harriet would previously have turned right to Ole Golly for help. Ole Golly would have provided her usual wisdom, reason, and level-headedness, advising Harriet on the best course of action and finding logical ways to soothe her mind when it is disturbed. Harriet feels the loss of Ole Golly now more than ever, so much so that she dreams about her. Since her parents do not know how to speak to and connect with her enough to help, they seek out a therapist to perhaps stand in for the absent Ole Golly as someone to talk to and advise Harriet. After one session, this does not appear to work; Harriet is guarded, and does not open herself up to just anybody.
An important lesson that Harriet needs to learn from this situation is how to apologize. Right now, she does not feel remorse for what she has done; she is only sorry that she was caught, and that her classmates are treating her in a way that she views as unfair. At the end of Chapter 14 she wants to make up with Sport and Janie, but she does not think to begin this process by apologizing—instead, she hopes they will have gotten tired of being angry, and that will be able to pick up as if nothing had happened. Until Harriet learns the importance of apologizing in order to repair relationships that mean a lot to her, she will remain stuck in this frustrating situation.