Automated infantry dolls - YoRHa. The M squad that was founded as a test case for male type models. There, it was a place that was like a school for the young boys to train. The story begins when the second batch, including protagonist No.9, joins the squad. The newcomers get used to the school life while interacting with their seniors from the batch before them. However, ones harbouring doubts towards the YoRHa squad begin to appear.