Merryn waits all night for her father to return from his fishing voyage. He never does. After a vivid dream showing her father trapped under the sea, Merryn is determined to save him. This unlikely heroine builds a small submarine from spare parts and sets off to rescue him. Along the way, she’ll make friends, discover lost civilizations and ruins, and upgrade her submarine to explore even deeper. The terrain and monsters of the deep are daunting, but Merryn’s courage, intelligence, and love for her father will help her overcome adversity.