Back in June 1983, the club participates in a game of "zombie tag". On their way home, they run into Irie, Tomitake, and Takano, who tell Keiichi about the yearly murders known as "Oyashiro-sama's Curse". However, he understands why his friends hid it from him and doesn't resent them for it. Regardless, this fails to reassure Rika, as she grows progressively depressed as the day of the Watanagashi Festival approaches.

Rika begins a new world with Hanyū, but is getting tired of seeing her friends commit the same acts that lead them to terrible mistakes, until Keiichi proves to her that people can change their destinies if they want.

Rika's plans are hindered by the appearance of Teppei, who much like in "Tatarigoroshi-hen", begins to abuse Satoko. Keiichi and the rest of the gang decide to find a way to release her from his clutches, but the government is reluctant to cooperate.

After getting a clue of the villain's betrayal, Rika tells her friends the truth behind the Hinamizawa Syndrome, and her connection with it. Meanwhile, the enemy moves on with their plan, eliminating any opposition.

Hanyū is physically introduced into the world as a transfer student to the Hinamizawa school, but forgets her role. After a brief meeting with Takano and Tomitake, she remembers the past worlds and informs Rika about the enemy's intentions.

Rika gather her allies and start to make plans, while obtaining more information about the enemy and those supporting their ambitions.

A new OVA series to commemorate the series' 10th anniversary.

A new OVA series to commemorate the series' 10th anniversary.