Ao no Shi, Boku no Koukai

One day, a sudden meeting is held at school. The news was that Ao Tamaki of Class 2B had passed away. Kitajima, who had been going out with Ao until last week, couldn't believe his ears when he heard the news. The beautiful and cheerful Ao was a much respected person at school, but why did she suddenly die? Kitajima wonders if it was his fault for saying goodbye to her last week, but he can't quite believe that she is dead. Then Rui, who was in the same class and club as Ao, appears in front of Kitajima. Rui has the ability to see the past related to an object when she touches it with her feelings, so she touches a protective charm made by Ao and sees the past... (Source: Kodansha, translated)