Hajime Yasaka, a thirteen-year-old boy from modern-day Japan, moves to the countryside to live with his grandfather. While on his way to his new home, Hajime stumbles upon a café called Ark, where he instantly falls for a beautiful waitress named Sayoko "Arashi" Arashiyama. Initially, Arashi pays no attention to Hajime until she takes hold of his hand and feels a connection between the two of them. Interestingly, Arashi is not an ordinary teenager. She is, in fact, the ghost of a young girl who died during World War II. Through her connection with Hajime, she can travel back in time and decides to seek his help in fulfilling her mission to save innocent people from the destruction of the war that took her life. Captivated by Arashi, Hajime boldly agrees to help her. However, as they delve deeper into her past, they realize that there are others who can also transcend time.