There exist in the world monsters called _Utsuro_, the favourite food of which is the bioenergy _nectar_, possessed by girls not yet of age. Despite belonging to an organisation called _The Garden_ that works to fight these monsters, Iruka Natsumi lives her life deathly afraid of being eaten by them. Yet then, a girl boasting overwhelming power appears before her! Will they reach the age of nineteen, or will they be eaten by the monsters first!?