Separated from Sosuke, Ponyo decides that she wants to be human and begins to conspire to return to land. Through magic, her wish to transform results in a metamorphosis which Fujimoto is, at first, able to counter. Not wanting to give up, the determined Ponyo breaks into her father's potions, accidentally spilling them. This barrage of magic causes the ocean to be inundated with large waves and a massive tsunami that affects fishing vessels, roads, and the many inhabitants of the island, but through it all, Ponyo is able to become human, find Sosuke, and meet his strong-willed mother, Lisa, who takes the two children home to wait out the storm.
Once home with Sosuke, Ponyo experiences the delights of the world. Unfortunately, the imbalance of magic and nature starts to have an affect on more than just the ocean current, so it's up to the bravery, adaptability, and love of young Sosuke to make things right again. Not only is Ponyo on the Cliff by the Sea a story about love, friendship, and determination, it's about the relationship between parents and children, respect of nature, and the magic of wishes.