In 1938, during the Second Sino-Japanese War, Wong Chia Chi, a young university student in Hong Kong, becomes involved with a patriotic theater group that aspires to do more than merely entertain. Moved by the troupe's fervent anti-Japanese sentiments, Wong is quickly drawn into a daring and ambitious plot to assassinate Mr. Yee, a high-ranking special agent for the Japanese puppet government in Shanghai. To do this, she must transform herself, from the inside out, into the sophisticated and alluring Mrs. Mak, entwining her fate with that of their target. The group's plan involves Wong becoming intimately close to Mr. Yee, employing seduction as a tool to lower his defenses.

As Wong Chia Chi navigates the dangerous waters of espionage under her guise as Mrs. Mak, she finds the lines between her real identity and her role blurring. This transformation is not just a physical undertaking but also an emotional ordeal, as she finds herself being drawn into a complex and perilous relationship with Mr. Yee. What starts as feigned intimacy evolves into something unforeseen, posing a threat not only to the mission but also to Wong's very essence. The stakes rise exponentially as their interactions deepen, leading to an intricate and suspenseful game of cat and mouse, with loyalty, desire, and deceit intertwining, underscoring the costs of betrayal and the price of allegiance in a time of war.