There are rumors of a grand treasure located within the local museum of Ashiwara and that this treasure requires a special key to unlock. But no one seems to know what this treasure is or even what the key looks like.
But Kei and Hikaru, two childhood friends, may inadvertently find out when someone seeks to claim the treasure for themselves and that action plunges their world into chaos.

Children have been disappearing mysteriously and it has been a major concern to many parents. One parent is found wandering about the streets asking people if they've ever heard of the swallow that cries at night. A waitress who works at a bar guides her to the bar and allows her to discuss her situation. In the bar, the waitress, a bartender, and a little girl listen. Once she has finished talking, she leaves. Now all the waitress and bartender has to do is wait. The little girl disappears from the bar and she appears on the streets. She finds and traces the girl in question and follows her to discover...?

Since the death of his family in a mysterious fire, Nanasawa Io has lived as an outcast. Students at his school fear and animals around him soon begin poping up dead. This brings about an investigation into Io by a group know as the Titans. The Titans goal is to hunt down and destroy Kagetsuki- people who have become possessed by malicious shadows. However, what the Titans soon discover about Io isn't what they expected
(Source: Fallen Syndicate)

Ishikawa Ginji is a young man who happens to hate any kind of business related to 'the other side', such as ghosts, superstitions or the occult. His despise for the matter is such, that he can quickly break up any girl if they show any interest in matters such as lucky charms or any kind of future reading.
One day, while he was self pondering about his life while ruining a date on a whim, he is suddenly kissed by an elementary school girl go goes by the name "Ageha", stating that she will use him to "wipe out every ghost in the world". While the sex appeal of an elementary school kid kiss was not enough to turn Ginji to her side, the fact that she "bought him" by paying a huge debt that he had acquired seems to work quite efficiently.