Omumedai summary:

From Storm in Heaven:In order to sustain a world on the verge of death, two groups, Blanches and Noires, vie for dreams.Every six months, the group with the fewer dreams has to send a number of members to the human world, where they will eventually die. Heki, a Blanche, fights to get ahead of the game, so he doesn't have to see his friends shipped off... again.