Henri is an idealistic young orphan who works at replacing light bulbs in the convent where he lives. Suddenly forced to leave the institution, he is faced with a world that is unknown to him. His job consists of adding light to people's lives, but his shyness keep him in shadow, ignored by everyone. He decides to help those who feel isolated as he does leave their obscurity behind, in the hope of being finally noticed himself. Henri is secretly in love with Hélène, the beautiful counter clerk who lives in a dark world devoid of light.