At the age of 18 Mimori Kiryu joins the organization HOLY as a research scientist. It's at her new job where she is reunited with Ryuho, a young Alter user from her past. While her kindness and desire to help sets her apart from those around her, she's also in the unique position of being the daughter of Tadanori Kiryu, a wealthy investor and main benefactor of HOLD and it's special unit of Alter users HOLY.