The episode opens with a flashback. The viewer's viewpoint is that of a child rushing toward a man and a woman standing at a fence at the edge of a gorge. The voice-over is Hanyū stating in her child voice that she "couldn't
do a thing," as the child pushes the man and woman through the fence and over the gorge. "I can do nothing but accept one tragedy after the other," laments Hanyū.
The scene then shifts to Rika's father arriving home having been driven by Irie. Irie tells him he is counting on him. Rika's father explains to his wife and Rika the Hinamizawa Syndrome. Rika recognizes that this is the basis of Oyashirosama's Curse, which her mother rejects. Her father explains that is it caused by a parasite, and there appears to be a "Queen Carrier" inherited in the Furude family. Rika asks if she is the "Queen," and her father responds that Irie believes it is important to study the "Queen." Rika then asks if all the villagers will be saved by studying her. Over her mother's objections, Rika agrees particularly if it will help Satoko.
We then move to Rika leaving an examination room announcing that her examination is over. Her father gives her money to buy a drink to which Rika responds that after all of the blood tests, she could use a "refill."
notes it is his father who, "committed multiple irrational acts of violence." Irie angrily retorts that his father suffered a head injury. Miyo condescendingly notes that no one believed him, and accuses him of continuing his research to clear his father's name. They then argue about guilt and logic, with Miyo claiming to ask for the consent of Rika's parents was "illogical." She also reminds him that his hands are already stained with blood. He accepts this.
Scene shifts to Irie being congratulated in a lecture hall by the same group of men who supported Miyo. He is given credit for the results of the research as Miyo looks on smiling. She is told she has a phone call. In what appears to be a hotel lobby, she takes the call and hears Koizumi praising her work. She notes that thanks to his support they have successfully isolated the pathogen of the Hinamizawa Syndrome.
We shift to Rika having her blood drawn by Irie. She asks how Satoko is doing, because she has learned from her brother that she has not improved. Irie states that they have some experimental drugs. When Rika asks him to use them on Satoko he protests they are still experimental. Rika then shifts into her adult voice to remind him that "nothing is 100% in medical science," and convinces him that there is no other way for Satoko. She trusts him since they worked together to save Satoko.
The scene shifts to Miyo explaining to the men who supported her that if something happens to the "Queen" within forty-eight hours the over two thousand villagers of Hinamizawa will become deranged. The men agree to emergency measures should this ever happen. Miyo narrates that the men are looking at documents they once trampled.
After the commercial break, Irie announces that "C103" has stabilized Satoko. Miyo reluctantly accepts this, but notes that the detective Ōishi Kuraudo has been asking questions. Ōishi makes clear to Irie that he thinks Satoko lied about the accident involving her parents. She claimed she was asleep when it happened; yet, she told people that her parents fell. Irie quietly realizes that Satoko was already suffering from Hinamizawa Syndrome, and her paranoia led her to push her parents to their death.
The scene moves to Irie asking Miyo about Rika's condition since she has a fever. Miyo off-handedly tells him she asked the Yamainu to dispose of the incident as an accident. She then notes that Satoko has improved. Rika's mother suddenly enters demanding the return of her daughter and blaming their experiments for her fever. She states she will refuse further participation, to which Miyo responds condescendingly that she signed a consent. Rika's mother states that she and her husband agree there will be no further experiments. The scene then shifts to the Furude home where Miyo and Irie ask for reconsideration. Rika's father gives them only three more months. Leaving, Miyo rants about Rika's importance to their research. Miyo resolves to do something about it and remembers "Oyashirosama's Curse."
The scene immediately cuts to Rika's father's father choking at a party, then the police finding Rika's mother's shoes at the edge of the swamp along with a note blaming the dismemberment of the Manager and accidental death of Satoko's parents as due to Oyashirosama's Curse and stating that she committed suicide to quell the curse. Ōishi finds this ridiculous.
Miyo laughs hysterically in her office claiming that she has won. She then receives a phone call where she learns that Koizumi has died. Walking in the rain--an important motif for her--after his funeral, she is stopped and brought to a meeting with the same men who supported her. They state that with Koizumi's death, they must reevaluate their project. They admit the intention of the Irie Institute was to study and develop a treatment for the Hinamizawa Syndrome with a secondary objective to develop military uses for it. They declare that work toward that objective is to be suspended immediately. Since the pathogen has been identified and treatment is successful, the project may end. Miyo protests that the very existence of the syndrome could overturn their understanding of humanity. The men then start to ridicule Miyo's paper as Takano Hifumi's thesis was ridiculed. They even ridicule Takano Hifumi's belief that a parasite could control human behavior. In a flashback, Miyo recalls her attempts to prevent the visitors from trampling on Takano Hifumi's thesis.
The scene shifts to her walking along a street in the rain as the voice over of the men state that research will be
concluded within three years. Crying, she feels she has lost and apolo- gizes to Takano Hifumi for her failure. She is suddenly stopped by a woman in a car which leads to the end titles.
After the end titles, Miyo sits in the car with the woman who states that "we wish to help you." She explains that a factional dispute arose after the death of Koizumi. She asks Miyo what her true objective is. She rhetorically responds for Miyo that it is to obtain recognition for Takano Hifumi's research and gain revenge against those who "trampled your grandfather's hard work under their feet." She offers her help--and hand--which Miyo accepts. In her mind, Miyo wonders if this is another test from "kamisama." She concludes that whatever the woman's real objective is, she does not care.
- Rika: "Disembowelment lover"
- Sonozaki Oryō: "SM Queen in active service, torture fetishist"
- Rena: "She may be a grandma with a house full of garbage!"
- Irie: "The perverted doctor who wants to give children in maid outfits injections!"
- Ichirō Maebera: "The Perverted pedophilic artist who just wants to draw Rika, Satoko and Hanyū naked!"