The fantasy-themed story centers on a middle school student on the swim team during a mysterious summer vacation.

While training at school during a drought a young girl faints from heat exhaustion. She instantly finds herself in the country side by a cool, clear river. Every time she falls asleep she is drawn deeper into this alternate setting.

The story is set in a world with a mysterious phenomenon known as "flow," and centers two people (and one cat) who make a living dealing with it.

Ichinose Shiki, an inheritor of the blood of Oni had lived out his entire childhood oblivious to this fact. However, when an unknown man comes rushing into his home in attempts to assassinate him, his foster father finally reveals the truth. In a world where Oni and Momotarou have never been able to coexist, join Ichinose in his struggle for power and unifying the two races!

(Source: MU)

Some live in the deep darkness behind your eyelids. Some eat silence. Some thoughtlessly kill. Some simply drive men mad. They are known as mushi—creatures that came into being shortly after life emerged from the primordial ooze. They still exist parallel to our own lives and can only be seen by a select few. As a mushishi, Ginko is one of the few who are aware of their existense, and this young man with a sardonic smile roams from place to place with the knowledge and skill to aid those unwittingly affected by mushi.

(Source: Kodansha Comics)