After her lover is murdered by a hostile organization, Yumi becomes a female spy and acquires the identity of "Black Sparrow" to seek revenge. With determination in her heart, she attempts to infiltrate the organization, only to find herself ensnared in a cunning trap set specifically for her capture. How will she respond to this conspiracy, and will her true purpose for vengeance finally be revealed? The story unfolds step by step, escalating with intense suspense.