The Sea Fairies, along with Sky Island, was intended to be parts of a long-running fantasy series to replace the Oz books. Trot is a little girl who lives on the coast of southern California. Her father is the captain of a sailing schooner, and her constant companion is Cap'n Bill Weedles, a retired sailor with a wooden leg. One day, Trot wishes that she could see a mermaid to her amazement the next day she does. The mermaids explain that they are benevolent fairies; when they offer Trot a chance to pay a visit to their land in mermaid form, Trot is enthusiastic, and Bill is too loyal to let her go off without him. Lyman Frank Baum was an American author of children's books, best known for writing The Wonderful Wizard of Oz. He wrote thirteen novel sequels, nine other fantasy novels, and other works.