One afternoon, Charles Wallace tells Meg of a "drive of dragons" in their back yard, where he and Meg thereupon discover a pile of unusual feathers. Later, Meg has a frightening encounter with a monstrous facsimile of Mr. Jenkins. That night, Meg, Charles Wallace, and their friend Calvin O'Keefe discover that Charles Wallace's "drive of dragons" is an extraterrestrial "cherubim" named Proginoskes (nicknamed 'Progo' by Meg), under the tutelage of the immense humanoid Blajeny, who recruits the three children to counteract the Echthroi.