When Makoto was forced to move away from his hometown, he left his childhood friend Minamo a harmonica and a promise: they’d meet again someday and eventually marry. Years later, Makoto and his sister Hinata return to Kazune, the city of supernatural powers. When Makoto hears a mysterious yet familiar harmonica melody being played on the roof of the school, he finds himself reunited with the girl of his all-but-forgotten childhood promise. The three and their friends happily go to school, spend time together, and slowly become more and more involved in the mysteries of a city which hides a great and disturbing secret – a secret that has touched all their lives more closely than they can possibly yet understand.
Morimiya Yorito is a normal student who has an abnormal obsession for the sky. One day, he meets a strange girl named Shihou Matsuri who shares his interest, but as fate may have it, she isn't a human; Matsuri is a Yaka -- a "woe of the night" -- who is immortal and cannot stand the sunlight. A strange man is chasing Matsuri, to use her powers, so Yorito decides to help her hide. What are the strange man's plans, and what secrets does Yorito's sister hide?
Both of these anime get pretty darn dark towards the very end, girls have supernatural powers, and finally romance, as well as what happened between main characters centuries ago, plays a significant role in the plot.