A message in a bottle? A fiery asteroid from space? A sea of magical mystical mermaids? In the deepest part of the ocean, unexplored by man and too deep for humans to swim, lives a little sea creature named Gillbert. One day, he will be king. But in the meantime, his playful curiosity takes him away from the kingdom on a journey of discovery.
Young Gillbert is the prince of the underwater world of Atlanticus. Together with his best friend Sherbert and mysterious new friend Anne Phibian, Gillbert is curious to where all these bottled messages floating throughout the ocean are coming from. Could the fiery Pyrockians from space have something to do with it? Or maybe it is something more mysteriously monstrous?