“Live” identity disorder, also known as “border”. “Life”, not “Personality” —Life. It is a new disease that suddenly appeared 10 years ago and changed about 7.6% of humankind to “Corpse”. Subjectively they are alive, but objectively they are “dead”. A high school girl detective × a border girl confronts unknown incidents that occurs in a society where the line between life and death is vague! !