Dusk Maiden of Amnesia

Teiichi Niiya is a first-year high school student who has just enrolled at Seikyou Private Academy. One day, when he gets lost in one of the school's old buildings, he meets a girl named Yuuko Kanoe, who reveals that she is a ghost with no memories. Teiichi decides to investigate her death by delving deep into the infamous Seven Mysteries of the school, along with Kirie Kanoe, a relative of Yuuko, and the oblivious second-year student Momoe Okonogi. Throughout the story, Teiichi and Yuuko uncover the truth behind these ghost stories and help those who are troubled, all while drawing closer to the truth behind Yuuko's death.