サルビアの娘 (Sarubia no Musume)

Background
"Daughter of Salvia" is Nanami-P's sixth Vocaloid work and is her most notable work with over 20,000 views. It's also Nanami-P's first song to feature Rin, with collaboration with Haruko doing the illustration. Mentioned in her mylist comment, the song tells a story of a girl growing up, and how Nanami-P mentioned she took it as a challenge on making Len singing in bass / low voice.

The song tells a story of the daughter of an inn keeper (Rin) meeting a traveler from a far away country (Len). Eventually they both fell in love. More of the story can be read on Nanami-P's novel site, with the title of novel being "In the Salvia Street".