It's the beginning of summer, and Sarah O'Shea and her dog, Claude, are going to visit the beach for the first time! Sarah's beach shoes, sunglasses, sunscreen and camera are packed. She has a brand new bathing suit, a new beach hat, and a tote bag full of books.

Once they arrive, Sarah and Claude chase seagulls, build sandcastles, find seashells, and play tag with the tide. But their adventure takes a surprising turn one evening when they discover there is more to the beach than sand and waves. Together they learn about the creatures who live by the sea. Come along with Sarah and Claude and discover the secret world of the beach.