Keiichi asks Rika for help, but when she and Satoko disappear, he starts fearing for the worse.

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 goes over to the Houjou residence to ascertain Teppei's existence and finds Satoko in need of clinical help. At the Furude Shrine, Keiichi discovers Rika's disemboweled body, and Satoko believes that Keiichi is the culprit and flees. After fruitlessly trying to convince her that he is not the murderer, disaster strikes the town of Hinamizawa.

Akasaka and Oishi find the kidnappers' hideout and rescue the boy. After discovering that their efforts were in vain because the perpetrators' demand was already conceded, he realizes the real meaning behind Rika's words to him.

Shion believes the Sonozaki family is connected to the acts of "demoning away" people in the village, especially that of Satoshi. She imprisons Mion in the dungeon and unintentionally kills her grandmother. Shion pretends to be Mion the next day and confronts Keiichi about the previous night's encounters, to which Keiichi still denies. Later, she finally discovers the ones responsible for Satoshi's disappearance.

Rena's madness reaches the peak to the point of taking all the school children hostage. With the police's help and working together with the rest of the group, Keiichi manages to defuse a homemade bomb Rena planted on the rooftop of the school. There, the two have a final confrontation and even though he is defeated, Keiichi manages to get Rena to realize she should have trusted and confided in her friends.