Aster-Colored Truth - S1.E10

Saikawa reveals that Nishinosono didn't interview Magata originally, but her daughter. Magata's original plan was for her daughter to kill her and Shindō, then take her place. Magata had also planned the computer "malfunction" years in advance. After Nishinosono interviewed the daughter, the daughter began to question the plan and her own identity and killed herself instead. Magata left her suite, pretending to be Miki, her alleged sister who never really existed, during the initial "malfunction", killed Shindō, and left the island along with the members of Saikawa's seminar group.