From MangaHelpers:

Kazuki, a teenage school girl, only gets to see her dad once every couple of months since he works an important and heavy scheduled job. Little does she know that her father is Tenrinou, one of the kings that rule the land of Sankai. Long ago, God created Shishuu, the modern world as we know it, and also created Sankai, where the humans and the human world is monitored and maintained. Aided by magical powers and lots of personnel, Tenrinou and Enraou, the other king, keep balance and peace in both worlds.

Kazuki is about to find out the truth about her father and how important she is to both the human world and the heavens. [vyc]