Is this a manga? http://www.mangago.me/read-manga/nekoka_danshi_no_shitsukekata/mh/c005/2/
I think it's an illustration of Nezumi and Shion from No.6 :)
Manga name: No. 6
Manga is No. 6
Is this a manga?
http://www.mangago.me/read-manga/nekoka_danshi_no_shitsukekata/mh/c005/2/