After being forced to move out of his apartment after he runs out of money, a young man named Tanaka decides to make a go of life on the streets. He finds a sheltered, deserted spot in the spaces between the city buildings, and things seem to be going fairly comfortably for him. After a short time, however, he discovers that the tiny corridors between the buildings seem to extend for miles in every direction, and that there is a tribe of violent people living in them, led by a strange old man. Will Tanaka be able to live in peace with them, or will he have to fight for his life?