Inunaki by Black Cyc - Adult Sex Game

Narusawa Takuto is a normal student living with his father and younger sister ever since his mother died. One day he is approached by a man claiming to be a lawyer who informs him that Takuto's maternal grandfather has passed away recently. For that reason, Takuto is forced to head to Masagomura, a small, remote village in the mountains to partake in the funeral of a grandfather he had never met.

In the midst of the ceremony Takuto meets a beautiful doll-like girl who claims to have met him in the past.

A secret festival held once in several decades. Legends of fugitives of the Heike clan lurking in the area. Having caught a glimpse of the mysteries concealed in this Godforsaken village, Takuto begins to pursue the truth...