This is a future era. Human beings have left the city for a long time. A new symbiosis system has emerged in the original dilapidated buildings. New life forms are integrated with the old buildings, and they complement the abandoned telephone booths.

When humans set foot on this lost soil again, they tried to invade and destroy this symbiotic relationship. At the same time, they tried to re-establish the old communication methods between people. Hence the "Reconstruction" operation.