Oct. 16th, 2012

Furude Rika lives in the quiet mountain village of Hinamizawa in Japan. The only 'modern' town nearby is about an hour's bike ride away and the local school is so small that all of the grades are smushed together into one building. Hinamizawa is noted for being a beautiful little village as well, but only a handful of tourists/outsiders ever visit.

Rika is the only daughter of the Furude family. There is a tradition/legend passed down the family that if their first born child is a girl for seven generations in a row, then she is the reincarnation of Oyashiro-sama, who is the village's protective deity. Furude Rika just so happens to be that special little girl. The Furude family commands a lot of respect as it is, being one of the "Three Ruling Families" that dominate the village politics (the other two are Kimiyoshi and Sonozaki) and also being the family that maintains Oyashiro-sama's shrine. However, as Oyashiro-sama's reincarnation, Furude Rika gets extra special treatment. The villagers all naturally spoil her and consider it "a blessing" when they happen across her. Many villagers call her "Rika-chama" to show their respect.

Oyashiro-sama, by the way, is a Deity guarding the village. “He”, in the past, protected them and helped them with an issue of “Demons” that co-existed in the village. Thanks to Oyashiro-sama, the villagers and the Demons (from the local Swamp) could live together peacefully. In honor of Oyashiro-sama, on June 19th, a festival called the “Watanagashi Festival” is held in “his” honor. The Furude House is deeply linked to Oyashiro-sama and his ability to protect people from the demon blood they have, due to the humans and demons co-existing. Though, a lot of that is a lie.

The Furude Family is approached by the Irie Clinic when Rika is maybe 7 or 8-- young, before hell breaks loose. Doctor Irie and Nurse Takano reveal to them that they are in Hinamizawa researching a disease called the “Hinamizawa Syndrome”. More Hinamizawa Syndrome information is here. But Rika’s family agrees to allow her participation in the research; her blood is the key to preventing the disease, so she needs to go to the clinic and donate blood for the research. Though, her mother is a bit reluctant, as she knows the constant blood donations will take their toll on her young daughter’s body.
However, all information about the research is kept secret among the family and research project members.

When she was around 5 or 7--- once again, age not specified, but later Akasaka returns to Hinamizawa with his 5-7 year old daughter and comments that she (Miyuki) is the same age as Rika was then, giving as an age frame-- Hinamizawa Village is in quite the pinch. The government wants to put Hinamizawa under water and turn the village into a dam. Though the government had offered to pay the villagers and help them move into the city, they stage an elaborate protest with Oyashiro-sama’s shrine (also called the Furude Shrine) as the base. The entire village bands together to try to convince the government not to sink their village.
Around this same time, Akasaka Mamoru also arrives in Hinamizawa. He’s a detective from Tokyo, investigating a kidnapping that may be linked to the Hinamizawa Dam project protests, but pretending to be a tourist. He meets Furude Rika at this time and she reveals for one of the first times in the series her “Frederica Bernkastel” side. Rika warns Akasaka that he needs to return to Tokyo or something awful will happen, and assures him that the Hinamizawa Dam Project will end without the village being sunk. She also predicts a chain of murders that will span for the night five years, ending in her own death.

Shortly afterwards, her predictions come true. Akasaka learns that his wife, Yukie, fell down the stairs. Though her unborn child is safely delievered, Yukie herself passes away. On that same night, June 19th, the manager of the dam construction project is murdered and dismembered. One of the killers disappears. Also like Rika predicted, the dam project is halted as a result of this tragedy.

The next year, a man and woman related to the dam project fall off a cliff while on vacation. They are the parents of Rika’s friend-to-be Houjou Satoko. Satoko’s mother’s body is never recovered. Satoko and her elder brother, Satoshi, move in with their aunt and uncle.
The next year, Rika’s own parents die. Her father is struck by a mysterious illness and her mother drowns herself in a “bottomless swamp”. Her mother’s body is never recovered. Mr Kimiyoshi becomes Rika’s legal guardian, but Rika lives alone in the Furude Shrine’s store house rather than her original house. Rika also takes on the role of Oyashiro-sama’s personal miko. The villagers support Rika’s living situation, but she is not alone for long.
The next year, Satoko’s Aunt is violently beaten to death and her brother Satoshi disappears/is “spirited away”. Rika invites Satoko to live with her when her uncle flees Hinamizawa and leaves her alone. For the next year, Rika and Satoko grow very close.

Finally, the fifth year of the curse rolls around. Just as Rika predicted. Tomitake, a photographer who visits yearly, At this point, the story branches off into different “worlds”. In some “worlds”, Keiichi goes crazy and kills Rena and Mion (Onikakushi-hen). In some “worlds”, Mion’s twin sister Shion goes crazy and kills everyone (Watanagashi-hen/Meakeshi-hen). In some “worlds”, Satoko’s abusive uncle returns and Keiichi wishes everyone in the village to die (Tatarigoroshi-hen). In some “worlds”, Rena goes crazy and locks her schoolmates in the local school and burns it to the ground (Tsumihoroboshi-hen/Yoigoshi-hen). And in some “worlds”, Satoko realizes something is wrong with Rika and tries to help her, but the entire village ends up annihanilated in a volcanic gas disaster (Yakusamashi-hen).

And in all of these “worlds”, Furude Rika dies. Is murdered, actually. Kidnapped, stripped of her clothes, put into light unconsciousness, and disemboweled on the steps of the Furude Shrine. No matter what, Furude Rika will always die.

But it isn’t over when she dies. When Furude Rika dies, her invisible friend Furude Hanyuu steps in. Hanyuu is the real “Oyashiro-sama”, a horned young woman who died in the past and continues to haunt Hinamizawa. She can only be seen by Rika, who is “Oyashiro-sama’s Reincarnation”. Hanyuu collects Rika’s memories and goes to find another world. She picks a point in this world before Rika dies and gives the Rika of that world all of her previous memories so that she can try to prevent her death.

And this has been going on. For a very, very long time.
Detailed versions of the worlds can be found here.