Keiichi Maebara, a student who recently moved into the village of Hinamizawa, is invited by his new friends at school to join their club. But while searching for treasure at a garbage dump with Rena Ryugu, he discovers the village is not as peaceful as it seems.

The annual Watanagashi Festival finally starts, and everyone has fun feasting and playing games. However, in the following day, Keiichi is interrogated by chief police officer, Oishi, about a crime that occurred at the night of the festival, and he starts fearing the villagers might be involved in this and other similar incidents, like Oishi suspects.

Delving further into the mysteries surrounding the village, Keiichi's paranoia grows after he starts to suspect that someone might be after his life.

Keiichi meets Mion's twin sister, Shion; the two are so identical that Keiichi can hardly tell the difference between them. It is also revealed that Mion has a crush on him.

Keiichi's parents leave for Tokyo for a few days. Helped by Satoko and Rika, who makes dinner for him, Keiichi learns about Satoshi, Satoko's older brother, and his mysterious disappearance on the night of last year's Watanagashi.

Keiichi comes to the resolution that he must kill Teppei. After brutally beating him to death with Satoshi's baseball bat, he buries the body, and on his way back home, Keiichi bumps into a suspiciously acting Takano.