Toumei Otoko to Ningen Onna: Sonouchi Fuufu ni Naru Futari

Akira Tounome is an invisible gentleman who runs a detective agency, and Shizuka Yakou is a mild-mannered human female who works there. Shizuka can always find Akira even when he turns completely invisible. A quiet love begins to blossom between them as the invisible man and blind girl grow closer to each other… (Source: Crunchyroll)