There are nearly no historical materials or documents, nor prior detailed research regarding Stefano Donaudy (1879 to 1925, Italian). I feel that such research would be significant and important. Accordingly, I have been researching Donaudy from the perspective of being a musician and have studied him from various viewpoints from the clues in his musical output. This paper consists of a Japanese translation of the text of the second act of Donaudy's fourth opera entitled Sperduti Nel Buio (1907). I believe that the translation of this opera will not only allow for the singing of this piece but also serve as didactic material for musicians studying the staging of the opera.