When the book opens, the narrator—a boy whose name is never given—provides basic information about witches, such as their focus on harming children, their methods, and their global distribution. They are always female, and they cannot be identified simply by their appearance. Even one’s own teacher, he says, might secretly be a witch.
The boy tells the reader that he has twice escaped from witches. Both events happened before he was eight years old, and he has his wonderful grandmother to thank for being alive to tell the truth about those encounters. Currently the young boy and his grandmother are living in Norway. Until he was seven he had lived in England, but during a winter family visit, his parents were killed in an automobile accident. Since their death, he has lived with Grandmamma, whom he adores.
Grandmamma knows a great deal about witches, including their taking children or turning them into animals. She wants to keep her grandson safe. While in most ways witches resemble human women, they do have a few features by which he can recognize them: bald heads (usually covered by wigs), claw-like hands (on which they wear gloves), toeless feet, and blue, ink-like spit. Her willingness to discuss them has limits, however; she will not say why she is missing a thumb.
As his parents had wished, the boy and his grandmother go to live in England. Grandmamma tells the boy that English witches tend to favor the use of potions that can turn children into slugs or bugs. Their parents, not recognizing them, might kill their own children. Most dangerous and cunning of all is the Grand High Witch of the World, whom the others visit annually. Grandmamma identifies as one of the “witchophiles” who try to learn more about them, such as where their meetings take place.
After the boy’s school term ends, they plan to take a holiday in Norway. Before the trip, however, the grandmother develops pneumonia. Rather than travel to Norway, her doctor suggests she recuperate further in coastal England. At their hotel in Bournemouth, the boy gets into some trouble when his new pet mice alarm the maid.
The boy stumbles onto a meeting of the Royal Society for the Prevention of Cruelty to Children. Secretly observing one of the attendees scratching her bald head under her wig, the boy determines that this is the witches’ society. When one apparently young, lovely woman removes her mask, he realizes that the real, shrunken, shriveled face beneath is that of the Grand High Witch.
She declares that their mission is to kill every child in England. They will do this through a network of sweet shops, from which they will sell candy tainted with "Formula 86 Delayed Action Mouse-Maker." Within a day of eating the candy, the children will turn into mice, and the adults will trap and kill them. As they agree to the plan, the witches sing a scary song about the children’s demise. They next review the composition of the formula, which includes ordinary ingredients such as mouse tails, but also components from exotic animals such as the gruntle, blabbersnitch, and grobblesquirt.
To test Formula 86, they give tainted candy to a boy named Bruno, who comes to the meeting room for candy. The narrator, still hidden, recognizes Bruno as a rich boy he met who liked to eat and complain. After eating the sweets, Bruno quickly turns into a mouse, but he escapes. The Grand High Witch changes the plan; instead of concocting the formula themselves, the other witches can get pre-mixed bottles, which she has in her hotel room.
The witches detect the boy’s scent, which they identify as dogs’ droppings. With the doors locked, he cannot escape. They capture him and pour Formula 86 down his throat. Feeling a burning sensation, the boy shrinks and grows fur, and his hands turn into paws. Before they can catch him, he scampers off and hides. Unconcerned, the witches leave.
When the boy encounters Bruno, they are both surprised that they can still speak in their human voices. The boy is philosophical about his new status. He reasons that being a child is just as hard, and just as dangerous, as being a mouse. There are some benefits, such as not having to worry about exams or money, and especially not going to war. Confident that his grandmother will accept him and understand what happened, he tries to reassure Bruno, who is very upset and expects a negative reaction from his parents.
The two mouse-boys reach the grandmother’s room almost without incident, although the boy bites the maid who sees them outside the room. Although she is clearly upset at what has happened to her grandson, Grandmamma is reassured that he is handling the transition well and relieved that he can still speak. The boy is determined to stop the witches’ plot to kill all the children, but his grandmother worries that this endeavor will be too dangerous.
Nevertheless, they form a plan to steal Formula 86 from the Grand High Witch’s room, which is directly beneath theirs. Grandmamma puts the boy-mouse into a sock and lowers him to the balcony. He manages to steal a bottle, narrowly escaping detection when the witches arrive in the room, and makes it safely back to his grandmother’s room.
Grandmamma takes Bruno in her purse to meet his parents, the Jenkinses. Horrified and incredulous at her explanation, they reject the entire premise and refuse to accept the mouse-boy as their son. The grandmother takes him back.
The boy next completes their plan: put the formula into the witches’ dinner so that they turn into mice before they can harm any more children. In the hotel kitchen, he learns that they have all ordered soup, and he mixes the formula into the soup pot before the waiter serves it. Before the boy can leave the kitchen, however, a waiter spots him, chases him, and cuts off part of his tail. He escapes into the dining room and joins Grandmamma, who has been waiting for him there. Bruno’s father then arrives, demanding Grandmamma produce his son. When Mr. Jenkins hears his son’s voice coming from the mouse, he finally accepts the fact of Bruno’s transformation.
As soon as Mr. Jenkins leaves, the Grand High Witch begins to scream. Soon all the witches turn into mice, and the waiters and all the other diners attack them. After Grandmamma takes Bruno to his parents, she and the boy leave—not just the hotel, but England.
They return to Norway, where Grandmamma makes her house more mouse-friendly. She is concerned about her grandson’s health and probable longevity: he will live longer than a regular mouse, but not as long as a human. The boy expresses his happiness at this good news. He tells Grandmamma, who is also likely to live about nine more years, that he would not want to live longer than her or have anyone else look after him.
As long as there are witches, the boy and his grandmother will have work to do. Having learned where the Grand High Witch lives, they will sneak into her home and learn the whereabouts of all the other witches—and make it their mission to rid the world of them.
Unlock This Study Guide Now
Start your 48-hour free trial and unlock all the summaries, Q&A, and analyses you need to get better grades now.
- 30,000+ book summaries
- 20% study tools discount
- Ad-free content
- PDF downloads
- 300,000+ answers
- 5-star customer support