Amnesia

The heroine wakes up on the morning of August 1 and discovers she has absolutely no memories of the past. A boy appears before her, and he introduces himself as a "spirit" named Orion. The heroine struggles to regain her memories under the guidance of Orion. She then gets a phone call, but she does not recognize the name on her mobile phone screen. She meets her apparent "boyfriend," despite not knowing his face.

Super sadly this is the only one of its kind