With forty-five color photographs, "Underwater" tells the story of children enjoying and exploring rivers and streams. Young readers can learn about creatures that live in freshwater: salamanders and toads, clams and fish, and more. An introduction to watersheds follows the story. The short text is written at an elementary school level, but younger children can enjoy the book if it is read to them. The photographs depict other children in a range of activities that include lifting, walking, swimming, examining crayfish, and taking photographs.