When siblings Francis, Mavis, Bernard, and Kathleen rescue a mermaid from a traveling carnival, they gain access to a hidden underwater kingdom. Using a magical rhyme to breathe beneath the waves, the children visit the city of Merland, where they find themselves entangled in a military conflict between the merfolk and an invading army of Under-Folk. Accompanied by their friend Reuben, they navigate a world of coral palaces, sea-urchin scouts, and giant lobsters, eventually attempting to negotiate peace through wit and courage before returning to their familiar terrestrial life.
This book serves readers who enjoy Edwardian fantasy where magic is governed by strict rules and consequences. It appeals to those interested in how legendary creatures might interact with children from a realistic, historical setting. Readers gain a perspective on the value of diplomacy over violence and the importance of loyalty. They finish the story with a concrete understanding of how Nesbit weaves classical mythology into a structured, imaginative adventure for young audiences.
- Published
- 1937
- Language
- EN
