We are a special team of the Administration of Space-Time Order, ordered to capture the wanted criminals in time and space. We have specially appointed the sons of the plane to be plane guards and work with us to capture the key criminals. ——From the Time and Space Order Administration
Every plane world has a book of order, which records the past and plans the future. If one day the world you live in encounters a huge change, it may be because the world order book has been tampered with.
The son of the plane is a plane life selected by the Book of Order. He can be her, it, or them.