Henrietta survived the slaughter of her family and was taken in by the Social Welfare Agency, a modern-day Italian government front that rebuilds broken girls with cybernetics and drugs them into obedient assassins. Each girl is paired with an adult male handler, and the pair forms a unit called a fratello. With her memories erased and her body rebuilt, Henrietta becomes one of the Agency's deadliest operatives, carrying out the state's covert killings at her handler's side.