Muhyo, Roji, and Nana visit a rustic hot spring resort to meet a client. They bathe in the hot springs while waiting for him... and then Roji catches a middle-aged man peeping into the women's bath at Nana. The man turns out to be their client and the author of a current best-selling novel series, "The Butterfly of the Night," Yontani Abeyuki.
That whole story is in 
The Butterfly of the Night!
!"هذه القصّة كاملة في "فراشة الليل
Die ganze Geschichte
¡Toda esa historia
está en Mariposa de la noche!
¡Esa es la historia
de Mariposa de la noche!
Toute cette histoire,
c’est l’intrigue du Papillon de nuit.
Ne La farfalla della notte
c'è scritta proprio questa storia!
A história inteira está
em Borboleta da Noite!
Это же сюжет «Ночной бабочки»!