The grimy maintenance worker was the janitor at the apartment building where Miyu lived. Despite seeing each other regularly, he was an "invisible person" to Miyu, a resident. Only when he pointed it out did she realize this. She felt ashamed of herself, because Miyu had also been ostracized by her friends as an "invisible" presence since puberty. Now, a strange and intense day was about to begin, with Miyu being suddenly assaulted and roughly handled by the grimy middle-aged man...