It's been seven years since Yuuichi Aizawa returned to the city he once lived in as a child. Though many things happened to Yuuichi in his past, he can only remember bits and pieces. His parents left Yuuichi in the care of Akiko once again, and this time, he will attend the same school as his cousin Nayuki. Many different girls appear before him, and some of them seem to know him from his past. Yuuichi must now recover his memories of the dark secrets that he erased from his heart, before he loses his precious ones.