Before Chise became the ultimate weapon, there was Lieutenant Mizuki, a veteran soldier injured in combat. She underwent an experimental procedure to become the first prototype of this ultimate weapon, allowing her to continue serving despite her injuries. Though successful, Mizuki’s development was limited as she was the initial test subject. When Chise, a more suitable candidate, is recruited into the military, Mizuki views her as naive and vulnerable. However, Mizuki, having undergone the same treatment, can read Chise’s thoughts, making her the only one who truly understands her. As the war intensifies and Chise’s powers grow, Mizuki delves deeper into the nature of the ultimate weapons, uncovering profound truths about Chise and her own existence.