Vol. 11 (part one) : After a year at boarding school, Shion Sonozaki flees the oppressive institution and secretly returns to her hometown in the mountains, telling only her twin sister Mion of her arrival. Though the Sonozaki family has kept the sisters apart to prevent conflict over who would become the next family head, Mion and Shion have remained close - enough so that Shion can easily impersonate her identical twin. When Shion encounters Satoshi Hojo in town, he is completely taken in by her "Mion" disguise. And Shion is quite taken with him. Vol. 12 (part two) : Unable to provide an alibi for the night of the Cotton Drifting, Satoshi becomes the prime suspect for the murder of his aunt! As her friend is hauled away by the police, Shion steps forward as a witness to Satoshi's whereabouts that night, exposing her true identity in the process. Shion may have saved Satoshi this time, but her actions have put her in serious danger. What will the Sonozaki family do to Shion when they learn of her association with Satoshi Hojo? And what will they do to Satoshi? Vol. 13 (part three) :One year after his disappearance, the police are no closer to finding Satoshi or solving his aunt's murder, and Shion is quickly running out of patience. Dressing alternately as "Shion" and "Mion," she positions herself as close to Keiichi as possible. Given that he too entered the forbidden Saiguden with this year's victims, Shion suspects he will be the next to be "demoned away." Shion hopes her actions will spur on the true murderer, so that when the serial killer does attack Keiichi, she will be ready. Vol. 14 (part four) : The demon of the Sonozaki family has found fertile soil in Shion's soul, and her fury rages out of control as she targets the last of those who are guilty of paining her beloved Satoshi. But how far is she willing to go? Will any torture or punishment fill the void left by her dear friend? Or will the sacrifices only rip greater holes in the tatters of her heart? The last pieces of the puzzle fall into place in the final volume of the Eye Opening Arc!