“Obedience is the key to happiness,” proclaims the government of this manga’s dystopian society–a tenet upheld by the National Welfare Act, a law that dictates standard immunizations for every first grader in the country (a country that greatly resembles modern Japan). What is special about these immunizations is that approximately one in one thousand of them contains a tiny capsule that settles itself in the recipient’s pulmonary artery. Then, on a pre-determined date sometime between the affected citizen’s eighteenth and twenty-fourth year, the capsule ruptures, killing the person instantly.