An ancient town is developing, and the city's museum holds art exhibitions. An ancient and authentic "Small Town Landscape is the Best in the World" is on display. Suddenly, the word "A" disappeared out of thin air, causing panic. On the way home from school, the heroine saw a black carriage driving on the road and disappearing out of thin air. The heroine therefore befriends the hero, and later discovers a mysterious tunnel, travels to a small town three hundred years ago, and finds out the reason why the word "A" disappeared. The hero and heroine fell in love and spent the night on the coast three hundred years ago. The heroine left the town the next day regardless of the hero's plea to stay.