Based on the adult manga by Akazawa Red.

After 1 year passed Shiro stopped working and returned to his hometown only to meet Loli whom he loved that is Akiyama Mizuki who was sitting in 4th grade elementary school at this time. Last year, he had expressed his love to Mizuki-chan and became his girlfriend. Therefore he wanted to make sure whether his girlfriend is still okay or has become a prostitute.

(Source: Nekopoi and Has Been Translated and Edited)