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.

Awakening stranded on a tropical island with no memory of what happened, Aster investigates a secret underwater world to find her missing sister, while Sam connects their disappearance to suspicious events in his own life

While mapping the ancient underwater city of Marinth in the Atlantic Ocean, submersible designer Hannah Bryson makes a shocking discovery: she may have finally uncovered the truth about the once-glorious city's mysterious demise. Long ago it was a thriving metropolis bursting with culture and life--Marinth's sudden disappearance has plagued scientists for years. But now, with her unexpected new findings, Hannah realizes that the ancient city's explosive...

Hailed as a hero for the new millennium, Austin is the leader of NUMA's special assignments team-- and the threat before him now is definitely special. A confrontation between a radical environmentalist group and a Danish cruiser has forced Austin and colleague Joe Zavala to come to the rescue of a shipful of trapped men; but when they investigate further, they discover that something far more sinister is at work.

When an enzyme capable of prolonging life is discovered deep beneath the North Atlantic, NUMA Special Assignments Team leader Kurt Austin and his colleague, Joe Zavala, investigate a killer who is targeting the enzyme's harvesters and researchers.

"Leah is changed. Months earlier, she left for a routine expedition, only this time her submarine sank to the sea floor. When she finally surfaces and returns home, her wife Miri knows that something is wrong. Barely eating and lost in her thoughts, Leahrotates between rooms in their apartment, running the taps morning and night. As Miri searches for answers, desperate to understand what happened below the water, she must face the possibility that...

Your brother and sister are deep-sea explorers that have discovered the ancient Lost City of Atlantis. Now you get to explore the mysteries of the sea, and you have 8 possible endings to your story.