Thirteen years ago, a section of Tokyo unexpectedly separated and began to hover above the city. The floating portion became known as Old Tokyo, while the ground‑bound area was called New Tokyo. No contact could be made between the two realms, and no communication, and time slipped by in silence while the world below remained oblivious. One day a young girl sensed that Old Tokyo would soon crash back to earth, and she embarked on a journey from the airborne city to the terrestrial one to rescue its inhabitants from the looming disaster.