Yuki was abandoned by her family at the age of 5 and till she turned 7 she lived on the roads alone and learned to tackle difficult situations alone and then she got refuge in an orphanage when she was almost 8,there too she proved to be the smartest and when she was 10,she left her orphanage and was found by a kind yet dangerous spy who worked for her country and recognized Yuki's potential and thats where her journey as an undefeatable spy began.