Himeno, a third-grade elementary school student, moves to a large mansion in the countryside, which turns out to be a ninja mansion. Akamaki, Aomaki, and Kiiromaki mistake Himeno for a princess, and she and the ninjas start living a strange life together. Meanwhile, a huge tornado is on the way...
The temple where Aiko lives has a strange sliding door that is only half painted. Aiko turns seventeen with an interest in painting but otherwise lacking ambition for her future. A mysterious man named Soji suddenly shows up and declares "kacchikene!" using the dialect spoken in Tokyo during the Edo period.
A girl who has recently moved temporarily from the city to a mountain school because of her father's work feels distant from her new classmates. Koichi gets interested in the girl, but he can't get close to her. The girl had wanted to return to her city life as quickly as possible, but by chance she happens to meet a real-life wind god…
Due to the destruction of nature, the disruption of ecosystem, and also massive wars using nuclear bombs and biological weapons since 20 centuries, the earth fell into ruins.
The ground was collapsed and polluted, and many kinds of plants and animals became extinct.
The earth encountered the 6th mass extinction: The Big Six. During the time, humans built the aero police to save endangered species. In this isolated city in the sky, various animals evolved over the years through genetically modified mating.
As a result, they started walking on two legs and acquired language.
Today, they have built a civilization and lead peaceful lives.
No one thinks of the outside, the terrestrial world any more――
One day, kids on the aero police find an unknown seed from the outside.
And their adventure in the unseen terrestrial world starts! ――
Without knowing that once they go down to the ground, they will never be able to come back...
[Source: STUDIO4°C]