The narrative follows Dorothy Dale and her vivacious friend Tavia as they return to Glenwood School and rejoin classmates, mixing everyday school life with episodic adventure. The girls' pranks, social scenes, and outings lead into a running mystery involving the disappearance of Tom Moran and other surprising incidents: snowbound isolation, a tunneling escape, a raid, imaginative set pieces such as the Castle of the Ogress, and a search that reveals secrets like the significance of Miss Olaine's ring. The tone balances light humor, camaraderie, and the girls' practical resourcefulness as they confront puzzles and restore order.