Katy loves the ocean and the waves so much that on the day of a promised trip to the beach with her mom she can barely contain her eagerness to get there. Her impatience launches her on a flight of fancy, a magical voyage of discovery. Along the way she meets a new friend, Amelia, who takes her to a wondrous undersea realm. As beautiful and enchanting as this new world is, Katy soon realizes that home is where she belongs, that she must return. When she arrives back home, another wonderful surprise awaits.