At an undetermined point in time, the usual gang plus Hanyuu in the flesh witness Takano about to be arrested by commandos in the forest after firing a shot at them that misses. Tomitake arrives to order them to take her to the Irie Clinic for treatment, as she’s in the late stages of Hinamizawa Syndrome.
Shift to early June 1984: a year has passed since the many unpleasant Watanagashi loops and murders. It’s a new year at school, and the absence of Mion, who is now attending high school in Okinomiya, is deeply felt by the gang, to the point Rika and Satoko duck out of club activities because it’s just not the same.
Still, the fact is, June 1983 came and went without the town descending into chaos and destruction…which is good! The question is how, and can the peace last? Rika accompanies Satoko to the clinic, where Dr. Irie not only makes an inappropriate comment about what Satoko should be wearing, but declares that after a year of treatment, she has been fully cured of Hinamizawa Syndrome (there’s no mention of Satoshi).
When Rika asks why he said before that sufferers could never be healed after a certain stage, he believes that changed because the root cause of the syndrome somehow changed somewhere along the way. Rika knows what changed: after a millennium, Oyashiro stopped mistrusting humans.
Rika intends to make a new era of peace in Hinamizawa official, so after she performs her offertory dance, she has Kimiyoshi and Oryou join her on the stage. She’d met with the other two main family heads the previous night, and they all agreed to make a joint announcement that the Dam War is over and Oyashiro’s curse wasn’t, like, a thing.
According to Rika, Oyashiro is happy with the town and returned to his slumber. With the weight of the priestess, Kimiyoshi and Oryou behind them, the words reach the people of Hinamizawa. Confident that new wind has lifted the town’s sails, Rika has Satoko join her at an Okinomiya book store, where she buys St. Lucia Academy study guides for the both of them.
It’s been Rika’s dream to attend the academy longer than Satoko knows, and now she wants to make that dream a reality for the both of them. Surely nothing bad can come of that in an arc called the “Village-Destroying Chapter”, eh?