Emerald and the lost treasure

"Emerald's class are spending the day sea combing -- picking up human rubbish that ends up on the ocean floor. When Emerald finds a precious teddy lying in a clump of seaweed she's tempted to keep it for herself, but the tag says it belongs to a human called Jack. Emerald asks her land-loving friend, Isadora Moon, to help her return it and together they embark on an exciting adventure across the land and sea!"--Back cover.