Book excerpt: THAT going to the seaside was the very beginning of everything—only it seemed as though it were going to be a beginning without an end, like the roads on the Sussex downs which look like roads and then look like paths, and then turn into sheep tracks, and then are just grass and furze bushes and tottergrass and harebells and rabbits and chalk. The children had been counting the days to The Day. Bernard indeed had made a calendar on a piece of cardboard that had once been the bottom of the box in which his new white sandshoes came home. He marked the divisions of the weeks quite neatly in red ink, and the days were numbered in blue ink, and every day he crossed off one of those numbers with a piece of green chalk he happened to have left out of a penny box. Mavis had washed and ironed all the dolls' clothes at least a fortnight before The Day. This was thoughtful and farsighted of her, of course, but it was a little trying to Kathleen, who was much younger and who would have preferred to go on playing with her dolls in their dirtier and more familiar state. "Well, if you do," said Mavis, a little hot and cross from the ironing board, "I'll never wash anything for you again, not even your face." * * * When four siblings journey to the seashore for a holiday, one of them unwittingly summons the sister ofa mermaid who is captured by a circus, and the children set out to save the imprisoned being. After a daring midnight rescue, the children's reward is an incredible journey beneath the waves and into the hidden kingdom of the mermaids. But they soon find themselves in a race against time as they struggle to prevent a war and save their new underwater companions! Here is a triumphant tale by one of the finest storytellers to ever write for children, and a pioneer of fantasy literature for this age group.