Mithril, a covert military group equipped with cutting-edge technology to combat terrorist operations, assigns a specialized team led by commanding officer Melissa Mao, to a delicate mission. Sergeants Sousuke Sagara and Kurz Weber are charged with safeguarding Kaname Chidori, an unwitting teenage girl possessing revolutionary scientific knowledge, labeled a "Whispered," from several organizations attempting to exploit her talents. Kurz and Melissa provide remote support, while Sousuke goes incognito as a classmate in Kaname's high school to closely observe her movements. However, his military background and unpolished social skills make it difficult to adjust to civilian life. His actions attract unwanted attention and create doubts in Kaname's mind. Despite Sousuke's sincere dedication, a terrorist strike exacerbates his mission. Identifying the ruthless mastermind behind the attack prompts Sousuke to prioritize Kaname's safety, at the expense of disobeying orders.