Thirteen-year-old Yasaka is a boy staying at his grandfather's house during his summer vacation. One day he entered a store and met Arashi, a beautiful sixteen-year-old girl working there. After trying to protect her from a man who claims to have been hired by her family to take her back by force, Yasaka ran away with her and now she stays at his grandpa's place with him. It didn't take much time for Yasaka to figure out that his new friend is far from an ordinary girl, as she possesses mysterious powers. The plot thickens when he finds a sixty-year-old picture of Arashi and another girl named Kaja, and to the surprise of all Kaja suddenly appears, and just like Arashi, her appearance hasn't changed at all since then.

[Source: Wikipedia]

The summer of a man's boyhood memories continue. Still on the cusp between childhood and being a man, he has linked with the ghost of a young woman from the World War 2 era. She, and the ghosts of other young ladies from that time, continue adventures alongside their linked partners, learning more about each other and travelling through time via their supernatural connection. While he struggles to see his crush on her come to fruition, meanwhile his friend—a girl his age, pretending to be a boy—seeks his attention as well.

[Source: Anime News Network]