This is a world of old concrete and steel bars, where the lingering scent of the Showa era blends with the modern day. A medium-sized local prison, a short distance from the city center. The walls are thick, the windows are set high, and the seasonal breezes barely pass through. Having committed a crime, you is placed in the same cell as Koichi. Yet, within that confined space, only their cell for two is oddly filled with a sense of "daily life" and a "man's presence."

Then, one day, after finishing dinner, the two return to their cell.