Taraimawashi-hen

Taraimawashi-hen (盥回し編) is the first arc of. It is primarily told from the perspective of Keiichi Maebara and explores his paranoia regarding the curse of Oyashiro. The events of the story are similar to the anime-exclusive arc.

Plot
After helping with preparations for the Watanagashi Festival, Keiichi Maebara and Shion Sonozaki have a clandestine conversation by the river about the history of the curse of Oyashiro. The following day, the club plays a variation of Clue, which Mion loses. As punishment, she is made to run errands for the other members. While doing so, she warns Keiichi to stay away from Shion.

Keiichi and Mion meet up at the Okinomiya library. Unbeknownst to Keiichi, the girl he is meeting with is actually Shion pretending to be Mion. "Mion" reveals more details about the curse of Oyashiro as well as the fact that Jirou Tomitake has been found dead. The following day, Keiichi and Rena Ryuuguu are confronted by Kuraudo Ooishi, a detective investigating the curse of Oyashiro. Ooishi informs Keiichi of the Sonozaki family's ties to the yearly incidents, however Keiichi is skeptical. When Keiichi returns home, he finds Rena waiting for him. Rena interrogates Keiichi on his meeting with the detective and leaves when Keiichi begins lying to her. Later, Ooishi calls Keiichi's house and informs him that both Shion and Mion have been missing since Keiichi's visit to the library. Ooishi elaborates that this is the second year in a row that the twins have disappeared after the Watanagashi Festival. Keiichi is concerned by this but tries to maintain a façade of happiness so that he doesn't ruin the dynamic he has with his friends.

Endings
There are two available endings for Taraimawashi-hen. Ending A is available during the first playthrough of the arc. Ending B becomes available after completing Tsukiotoshi-hen.
 * Ending A: Ten years later, Ooishi meets up with Mamoru Akasaka to visit Mion in the hospital. While the majority of the villagers in Hinamizawa fell victim to the Great Hinamizawa Disaster, Mion survived as she was locked in the basement of the Sonozaki Estate with a head injury. As a result of this injury, Mion sustained severe memory loss and is incapable of recognizing Ooishi or Akasaka. Instead, Mion attempts to play cards with them, believing them to be her friends from the club.
 * Ending B:

Villagers

 * Keiichi Maebara
 * Shion Sonozaki
 * Mion Sonozaki
 * Rena Ryuuguu
 * Rika Furude
 * Satoko Houjou

Outsiders

 * Jirou Tomitake
 * Kuraudo Ooishi
 * Mamoru Akasaka

Mentioned

 * Oyashiro-sama
 * Satoshi Houjou

Deaths and Disappearances
All deaths and disappearances are listed only as they are told in  and apply only for the individual arc, not the overall series.

Deaths

 * Jirou Tomitake, died of blood loss after clawing out his own throat June 19, 1983 on the night of the Watanagashi.
 * Everyone in Hinamizawa not listed otherwise, died June 1983 of gas poisoning during Great Hinamizawa Disaster.
 * Some people who used to live in Hinamizawa, started showing erratic behavior right after Great Hinamizawa Disaster. Some died mysteriously in hospitals, while others started dying in other strange ways.

Disappearances

 * Shion Sonozaki, disappeared June 1983, shortly after the Watanagashi Festival.
 * Mion Sonozaki, disappeared June 1983, shortly after the Watanagashi Festival. She was later found in the basement of the Sonozaki Estate with severe memory loss.

Trivia

 * Tarai mawashi (literally, "pass the basin around") is a Japanese idiom, referring to someone avoiding a necessary but unpleasant task by passing the responsibility on to another, similar to the American English phrase "passing the buck."
 * Taraimawashi-hen is the shortest visual novel arc in.