In a world where every person must count something from birth, the young Hina roams the lands in search of the legendary Red Baron. However, it soon becomes clear that this quest is far from safe, as one's count drops to zero, leading to being sent into the abyss. There are also those who seek to steal the counts of others to increase their own. Author: Suu Minazuki, Illustrator: Suu Minazuki.