Tamamayu ~Miserareta Mitsu no Ito~

Mysterious girl Shoko suddenly transfers to main character's school. One day she confesses to protagonist, but gets rejected. She says she has an ability to control the darkness and is drawn to protagonist's inner darkness. But her attempts of mental control get blocked. At that point Shoko starts to involve people around protagonist. Will hero engulf in darkness or break free from it?

[From vndbreview]