When the Octonauts, a team of eight animal underwater explorers, meet a frowning fish, they try their best to make it smile.

The Octonauts use their underwater Octopod base to travel to the mysterious Sea of Shade to discover why all the world's shadows have gone missing and convince the Shade King to return the shadows.

In this story inspired by Jules Verne's "20,000 Leagues Under the Sea," Ana Dakkar, 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, makes astounding discoveries about her heritage and puts her leadership skills to the test against deadly enemies from a rival school.

Pitt must find a missing nuclear sub before the sea explodes and before assassins get him.

"The purrmaids' homework assignment is to find something special to bring to class. Will they be brave enough to swim far away from Kittentail Cove and explore Tortoiseshell Reef to find the perfect thing? Or will they be scaredy cats?"--

In the midst of an international crisis, Heidi Milligan, a beautiful, brilliant American naval commander, accidentally discovers an obscure reference to the long-buried North American Treaty, a precedent-shattering secret pact between the United States and Great Britain. The President believes that the treaty offers the single shot at salvation for an energy-starved, economically devastated nation, but the only two copies plummeted into the watery...

The Krewe of Hunters must find an ancient shipwreck and save divers from the demons aboard, in book 7 of the fan favorite series from New York Times bestselling author Heather Graham. It is 1898. Bound for Chicago, the freighter Jerry McGuen goes down in Lake Michigan, taking with it every man aboard. But what other fate could befall a vessel carrying the ill-gotten sarcophagus of an Egyptian sorcerer? Now: A veteran diver and "ghost ship" expert...

The reader is taken beneath the surface of the ocean in a diving bell on an expedition to find Atlantis and can choose between alternative adventures, each leading to forty-two possible endings.

A discovery by submersible designer Hannah Bryson suggests a possible cause of mythical Atlantis's mysterious demise that has potentially cataclysmic consequences for the modern world.

When Neil, Sam, and Biggs are captured by Captain Jolly, a pirate who needs their video-game skills to destroy the world, the Nerdy Dozen must save the day in an underwater adventure.