Mrs. Whatsit, Mrs. Who, and Mrs. Which appear on Ixchel in response to Meg's calls. However, they reveal that they are helpless to save Charles. Mr. Murry requests them to help him in tessering so that he can try to retrieve Charles from Camazotz, but Mrs. Which clearly says he will not be successful. Calvin asks to be sent after Charles, but he, too, is refused. After a long silence, Meg realizes that everyone wants her to go back to Camazotz and rescue her brother. Scared and overwhelmed by the responsibility, Meg cries out that she cannot go back. Gradually, she realizes that she is the one who is most likely to get through to him as she is the closest to him. Mr Murry and Calvin do not want her to go but Mrs. W's convince them that it is for the best. Meg says goodbye to her father, Calvin, and Aunt Beast, and also apologizes to her father for her emotional outbursts. Mrs. Which tells Meg that she will tesser with her through the Black Thing so that Meg arrives at Camazotz safely.
Once again, each of Mrs. W's presents Meg with a gift: Mrs. Whatsit bolsters the force of her innate love. Mrs. Who gives her a blessing from the New Testament. Mrs. Which strengthens in her the one thing that she has but IT does not have. However, Meg must find this thing for herself. Meg arrives safely on Camazotz after tessering with Mrs. Which and heads directly to the domelike building where IT is waiting for her. Inside, Charles is crouching behind the dais containing the disembodied brain. His eyes roll and a tic in his forehead pulses to IT's revolting rhythm. Meg tries to think hard about Mrs. Which's gift. But Charles mockingly says that she has nothing that IT does not also have. Meg thinks that her weapon cannot be her ability to resist, her anger, or her hatred, for IT has all of these things. Charles suggests to Meg that Mrs. Whatsit hates her, and at that moment, Meg realizes the one thing that she has that IT does not have is: love. She cannot possibly love IT but she can love Charles. She calls out to him with all the force of her love. And, he runs into her arms, both the children tesser together through the darkness. When they come out from the darkness, they find they have rejoined Calvin and Mr. Murry in the twins' vegetable garden back on Earth! After a happy family reunion, the three Mrs. W's appear. Mrs. Whatsit apologizes for not saying goodbye as Mrs. W's are now busy with a new mission. She starts to describe the mission but a strong gust of wind surrounds them, and before Mrs. Whatsit can complete her sentence, the three celestial bodies are gone.