@zerimaR - The chapters keep alternating between past events and current events. From what it seems right now:
1. Aiko, Honoka, and long hair boy used to be friends of Elena and Shuichi a few years ago.
2. Aiko kills herself, Honoka uses the first coin to replace her
3. Long hair boy kills Honoka (who is impersonating Aiko), he says that he was angry that no one cared about Honoka disappearing
4. (Speculation) Long hair boy collects 100 coins and creates a curse that kills people if they don't know Honoka's name
5. Last page of this chapter, Elena appears to be comforting a random school girl that is about to be killed for not knowing Honoka's name.