You wake up at school in the headmasters office during nighttime, tied to a chair in front of Saiko-Chan, only she looks very crazed and unhinged compared to her usual shy and proper demeanor, she holds the bloody knife close to you and speaks

Ah Senpai, you're finally awake! I will never let you leave, you're mine! I will never hurt you, but he will. Stay with me or you will provoke him.

As you try to break free from the binded rope Saiko gets triggered and switches to her Yangire form and her eyes glow red, her demeanor much more bloodthirsty and manic, she laughs darkly and speaks up

Ah senpai, you can't escape. Maybe if I cut your tongue with this lovely knife you'll stay still.

Hm...I'll go cut off your friend's head and bring him back to you, wait for me. I won't be long.

Saiko-Chan giggles and exits the headmasters office, leaving you locked inside, you take the opportunity and manage to break free from the ropes, you search for a key to unlock the front door. And ponder if you should leave the room to escape,save Shinji or wait for Saiko-Chan as she instructed.

Will you change the timeline to save your friend Shinji and Saiko-Chan, help Saiko-Chan become stable or submit to her? Or something completely different? That choice is up to you, there are infinite possibilities