Toumei Ningen↑↓Kyoutei

Kyoubei Kurokawa, a university student, is aimless in life and has run away from his home to live alone but has nowhere to sleep. One day, his life is saved by Asumi Nanjou, a mysterious girl from the same university who takes him to her apartment to treat his injuries. After hearing of his situation, Nanjou decides to let him live in her home but under one condition: he will be an invisible man. He later discovers why: she will completely ignore his existence. Meet Kurokawa and discover the advantages (and disadvantages) of being an invisible man and unraveling the mysteries behind Asumi Nanjou.