She is a family-ruining jinx abandoned by her clan, who cross-dresses as a man to infiltrate the Hale Clan for revenge. He is the frail young master of a martial arts academy, who requires a pure yin constitution to survive. A reckless night at the Serene Hill Inn left a vermilion birthmark on her collarbone, which became a karmic bond weighing on his heart. She thought her every calculated move was only for a secret manual, but he gradually recognizes that she is his childhood playmate 'Tang Tang'. When impostors frame her and conspiracies come to light, the jade plate token capable of mobilizing 300,000 troops finally points to the secret of her identity. This approach that began with calculation eventually becomes mutual salvation for two lonely souls.
