Siblings Meg and Charles Wallace were troubled about their father, who had been missing for years. One day on a walk in the forest, they came across a boy named Calvin, and quickly became friends. That evening, they met three odd women, Mrs. Who, Mrs Which, and Mrs. Whatsit, who claimed to be able to wrinkle space.
Mrs. Who, Mrs. Which, and Mrs. Whatsit took Meg, Calvin, and Charles Wallace to another planet by wrinkling space. There the three ladies told them that it was possible to save Charles' and Meg's father. Mrs. Whatsit showed them an evil force that was taking over the galaxy, and told them that their father was trapped behind it. They could try to save him, but only if they were willing to risk everything.
The three women then took them to the planet Camazotz, where their father was being held, but had to leave the children to continue on their own. Meg, Charles Wallace and Calvin encountered a man that was being controlled by the evil force IT. Only after Charles Wallace gave up his mind to IT were they able to find their father. Meg and Calvin fought hard and eventually freed her father, but in order to save themselves, they had to leave Charles Wallace behind.
Meg realized that she must be the one to save Charles Wallace from IT. After transporting Meg back to the evil planet, Mrs. Which told her that she had something that IT didn't have, and that was her greatest weapon. Meg realized that IT didn't have love for anyone or anything. The only way to free Charles Wallace from the control of IT was to give him the most powerful love she could. After Meg rescued Charles, Mrs. Which quickly took them off of the planet to safety.
Mrs. Who, Mrs. Which, and Mrs. Whatsit transported Meg, Calvin, Charles Wallace, and Mr. Murry all back to Earth. As soon as they got there, the Murry family and Calvin were all reunited. Meg's mom was beside herself with joy. Though the three women had mysteriously disappeared, Meg, Calvin, and Charles Wallace would never forget their adventure.