A Swiftly Tilting Planet is the third book in the Time Quintet. It is set about ten years after A Wrinkle in Time.
Fifteen-year-old Charles Wallace and the unicorn Gaudior undertake a perilous journey through time in a desperate attempt to stop the destruction of the world by the mad dictator Madog Branzillo. They are not alone in their quest. Charles Wallace's sister, Meg - grown and expecting her first child, but still able to enter her brother's thoughts and emotions by "kything" - goes with him in spirit.
- Meg Murry
- Charles Wallace Murry
- Madog Branzillo
- Branwen Zillah Maddox O'Keefe