"A Swiftly Tilting Planet" is a science fiction novel by Madeleine L'Engle, part of the Time Quintet series. The story follows Charles Wallace Murry, who, with the help of a unicorn named Gaudior, travels through time and space to prevent a catastrophic event. The narrative explores themes of love, courage, and the interconnectedness of all beings. As Charles Wallace journeys through different time periods, he encounters various characters, including Meg Murry and Aunt Beast, highlighting the importance of understanding and compassion in overcoming challenges.