Hannah, Zachary, and Sarah Emily are spending the summer at their great-aunt Mehitabel's house on faraway Lonely Island. There, in a cave hidden high above the ocean, they discover a fabulous creature: a glittering three-headed golden dragon with a kind heart, an unpredictable temper, and a memory that spans 20,000 years. Transported by the magic of the dragon's stories, the children meet Mei-lan, a young girl in ancient China; nineteenth-century cabin boy Jamie Pritchett; and, in more recent times, Hitty and her brother, Will, who survive a frightening plane crash on a desert island. In this fluidly written novel, Rebecca Rupp explores what three children from the present learn from the past - and from an unlikely but wise and generous friend.