Higurashi: When They Cry – Kai

In order to save Satoko, who is terminally infected with the Hinamizawa Syndrome, Rika offers herself as a test subject for Irie and Takano's research. More light is shed into the deaths of Satoko and Rika's parents, and its involvement with the legend of Oyashiro-sama's curse. (Source: When They Cry Wikia)