The three Davis children aren't too thrilled when their mom, a mystery writer, tells them that they are going to spend the summer on Lonely Island at an old Victorian house owned by their Great-great aunt Mehitabel off the coast of Maine. They all had plans for the summer that did not include hanging out with each other on a deserted island. But when they arrive, they find a letter left for them by Mehitabel, telling them to go explore Drake's Hill. When they get there, they find a cave and inside the cave, slumbering away, is a tridrake(a three-headed dragon). One of the heads awakens and assures the children that they are in no danger, the tridrake is a vegetarian. As the weeks progress the children become friends with Fafnyr Goldenwings and each head awakens in turn and tells the children a story and each story relates to the life of each child.
The first head tells the story of a young girl named Mei-lan in ancient China and how she learned to accept responsibility by helping her village. The second head tells of saving a young orphan boy from pirates and teaching the boy about sharing in the process and the third head tells the story of Hitty, a timid young girl who, with the help of the dragon, learns self-reliance after she, her brother and father crash-land during an attempt to fly around the world. The children soon realize that the stories, each told by a different head in the order in which they came alive, were also metaphors for their lives and feelings. They have a much greater respect for Mehitabel when they realize that she is the young girl in the third story.
The stories each dragon tells are not new, they draw upon other stories and legends, but Rupp has a way of telling the stories through the dragon's eyes that adds a freshness and a sense of adventure to each one that makes it seem new. Children learn important lessons about life, responsibility and friendship without realizing they are learning a lesson. This is a smoothly written story that entertain even the pickiest of young readers.