Under a forgotten bridge, a hidden staircase spirals down into a sea no one can see. Maia, a brave sixteen-year-old with more curiosity than caution, and her fluffy white dog Lio, follow the steps into a world where the water is invisible and everything living within it is invisible too. They can breathe beneath the surface, but they cannot see a single wave, fish, or current around them. Guided only by sound, scattered footprints on the seabed, and strange glowing bubbles that drift like lanterns in the dark, Maia and Lio must track down an entire civilization that has vanished without a trace. As they go deeper, they discover that the ocean itself seems to be hiding secrets on purpose, and that something down there does not want to be found. Every clue could mean rescue, and every wrong turn could mean they never find their way back to the surface. This action and adventure thriller blends suspense, mystery, and heart as a girl and her loyal dog face an underwater world unlike anything ever imagined. A perfect pick if you love cheap ebook finds, ebooks under 1 dollar, kindle ebooks on sale today 2.99, kindle ebooks under 2 dollars, ebooks under 2 dollars, or ebooks under 3 dollars, this is a gripping, affordable read for adventure and thriller fans of all ages.