When the shadows in the ocean go missing, the Octonauts, a team of eight animal underwater explorers, must travel to the Sea of Shade to find them.

Ana Dakkar is a freshman at Harding-Pencroft Academy, a five-year high school that graduates the best marine scientists, naval warriors, navigators, and underwater explorers in the world. Ana's parents died while on a scientific expedition two years ago, and the only family's she's got left is her older brother, Dev, also a student at HP. Ana's freshman year culminates with the class's weekend trial at sea, the details of which have been kept secret....

Join global sensations, the Octonauts, in an exciting new title in the classic picture book series that inspired the phenomenally successful animated TV show, broadcast around the world. The Octonauts are a crew of cute animals who love to explore the big blue ocean. From their underwater base, the Octopod, the eight intrepid friends are always ready for fun and excitement! It was a sunny day under the South Pacific Ocean when...ALERT! ALERT! ALERT!...

When the Octonauts, a team of eight animals who explore the ocean, discover a bleached and abandoned coral reef, they learn about the important relationships among animals, plants, and their habitats.