Kao no nai Tsuki

Koichi Hayama has recently suffered the loss of his step-parent due to a traffic accident. Taking a break from college to join in the funeral proceedings, he is confronted by a strange-yet-familiar young woman. He keeps having these recurring dreams of her, but doesn’t hold any memory of who she really is. This is because he only remembers bits and pieces of his childhood. She, however, says she knows him. Soon they both strive to solve the mystery of his missing memories, and his true origins while staying at the Kuraki temple--which is inhabited by a few more lovely ladies.

[From White Masq]