Amidst the perils lurking around the world, individuals seek protection to safeguard their lives. For those in search of security, the girls of Tercio stand as a beacon of hope. This private security company hires individuals with a unique genetic lineage who embody an impressive skill set. Apt in their roles as bodyguards, the girls are not merely a display of charm and character but rather, epitomize competency. As Tsukasa Yakuouji, a headstrong sword-bearing protector executes her responsibilities as a Tercio bodyguard, she feels as if there is an elusive quest beckoning her.