After a three‑year undercover mission, anti‑drug policewoman Lin Wan returns, only to learn her lover Shen Xingzhi has died in duty. To uncover the truth, she infiltrates the Black Gold Society, and makes a shocking discovery: Shen Xingzhi is now the drug lord’s adopted son. The two reunite through perilous trials, gathering criminal evidence in tacit cooperation to destroy the drug den. However, long-term poisoning by Bai Wanjin leaves them addicted. Lin Wan goes to Yunnan for rehabilitation. Fully recovered three years later, she returns to the anti-drug frontline.
