Keita lived together with his weak imouto Maya while being supported by their relatives. He didn’t have any memories prior to his childhood accident, but otherwise he’s enjoying his life. Lately he often had a strange dream about a girl dressed in white – a dream which seemed to grip his heart tightly. One day at Maya’s suggestion, they headed to a place they’ve been to in the past, which he didn’t remember due to his accident. They reached a small shrine on a hill where a mysterious girl named Tsukumo appeared. She embraced him and said, “I’ve been waiting, onii-chan”.