In a world where an infection dubbed the "10-Year Disease" has taken over the world, half of all children will die before the age of 10. Our protagonist is Clair, a demon-loving 10-year old who dreams of becoming infected with the disease! While tensions with her priest grandfather rise, she gets the disease! With only a little life left to live, what kinds of trials will Clair and her grandfather go through!? A serious story of action and survival awaits in CoroCoro Weekly!