Kaitei Sanman Mile

A bold journey into the unknown awaits when a young boy and his courageous sister stumble upon a world-altering secret. Deep beneath the waves, a fantastical civilization thrives, but their existence is threatened by an impending ecological disaster that could engulf both their realm and the surface world. With adults proving utterly incapable of grasping the true scope of the danger, these two intrepid siblings must take matters into their own hands. Their adventure plunges them into a vibrant, perilous undersea landscape, where ancient legends come to life and colossal beasts roam. United with an unlikely ally from the fantastical deep, they embark on a desperate mission to avert catastrophe. It's a thrilling race against time, where the fate of two worlds rests on the shoulders of the young and the brave.

✦ AI-drafted summary