Chapter 1: The Secret
* Summary: Meg Murry, her younger brother Charles Wallace, and their new friend Calvin O'Keefe discover a strange "tesseract" in their father's attic. The tesseract is a device that allows them to travel through space and time.
* Example: "A tesseract is a wrinkle in time. It doesn't have to be a straight line."
Chapter 2: The Trip to Camazotz
* Summary: The children use the tesseract to travel to the planet Camazotz, a totalitarian world where the people are ruled by IT, an evil brain.
* Example: "The city was like a huge machine, all steel and glass and concrete. It stretched as far as the eye could see."
Chapter 3: The Black Thing
* Summary: The children encounter a monstrous creature known as the Black Thing, which represents the evil that is spreading throughout Camazotz.
* Example: "It was a huge, black, shapeless thing. It had no eyes, no nose, no mouth. It just hung there, suspended in the air."
Chapter 4: The Happy Medium
* Summary: Meg and Charles Wallace meet Mrs. Who, an eccentric woman who helps them understand the nature of the evil on Camazotz.
* Example: "I'm a Happy Medium. I see things. I hear things. I know things."
Chapter 5: The Rescue
* Summary: Calvin is captured by the Black Thing, and Meg and Charles Wallace must rescue him.
* Example: "Meg grabbed a handful of flowers and threw them at the Black Thing. The flowers exploded into a cloud of light, and the Black Thing roared and disappeared."
Chapter 6: The Return
* Summary: The children escape from Camazotz and return home, but they are still haunted by the evil they have witnessed.
* Example: "They were home. But they were not the same as they had been before they left. They had seen the evil that is in the world, and they could never forget it."
Chapter 7: The Whatsit
* Summary: The children learn that the "Whatsit" they found in their attic is actually a benevolent being that has been helping them fight against the Black Thing.
* Example: "The Whatsit was a star. It was the star that had guided the children to Camazotz. It was the star that had helped them defeat the Black Thing."