After watching Rika’s dance, Rena shows Keiichi how to perform the cotton-drifting ritual on the river to honor Hikamizawa’s local deity, Oyashiro-sama. Then she heads off on her own, and Keiichi spots Tomitake talking with a blonde woman. He doesn’t interrupt in case it’s something romantic, but we see that Rena is staring them down from the woods.
The next day Keiichi is called out of class to meet with Ooishi, a prefectural detective investigating the recent disappearance of both Tokitake and the woman, Takano. Turns every year out of the last four, people have died from what the locals believe to be Oyashiro’s curse on the day of the festival. He asks Keiichi to keep his eyes and ears open and to report anything strange that happens.
The next day, June 21, Keiichi does just that, overhearing Mion and Rena talking about Tokitake’s disappearance and whether he was “demoned away”. He and Ooishi go to a cosplay cafe, where the detective tellls him the village believes in a form of spiriting away involving demons—not those of hell but the kind that eat people alive. Every year, someone falls victim to the curse and someone is demoned away.
While walking with Rena on the afternoon of the 22nd, Keiichi tries to pry further into what she and the others might be hiding with him, and her cheerful personality drops and turns the accusations on him. Accusing him of lying and hiding things she witnessed him doing, including hiding the magazine at the junkyard and talking with a random stranger. She eventually returns to “normal”, telling Keiichi to admit they both have things they want to keep hidden and leave it at that.
Keiichi is still well and duly spooked. That night, he gets a call from Ooishi, who has been digging into Rena’s past. While she claims to be new to Hinamizawa, it turns out she and her family are originally from the village. She also had an incident at her old school in which she smashed all of the windows, was diagnosed with neurological and psychological conditions, and prescribed medicine and therapy.
In those sessions, Rena would often speak of Oyashiro-sama appearing as a spirit in her room every night. The phone call is then interrupted by Keiichi’s dad, who has a tea set for him and his visitor…he assumed Rena had come to hang out with Keiichi, but she snuck in and eavesdropped on his call. That can’t be good!
Just as the ending sequence starts with beautiful happy moments between the five friends only for the imagery to turn traumatic and bloody, so too is the bucolic affableness fading away. Rena isn’t afraid to show her dark side to keep Keiichi in line, but now it’s a good bet he now Knows Too Much, which means he must be…Dealt With.