Socialite Su Wenli arrives in Shanghai from Paris to find an old friend's husband has dropped dead before finishing his morning cup of coffee. After ignoring instructions from police inspector Luo Qiuheng to stop intervening in the case, Su Wenli finds evidence that the victim was poisoned -- but who would want the prominent businessman dead?

Though evidence points to the businessman's female servants, Taozi and Li Qiaomei, as the murderers, Su Wenli is determined to clear their names. Later, Su Wenli finds the real killer waiting for her in an unlikely location.

After Su Wenli establishes the Miss S Detective Agency and recruits Taozi as her new employee, the pair embark on a train to Nanjing. There, Su Wenli discovers a passenger has disappeared, propelling her on a night-time search that leads to a shocking discovery.

When the deceased passenger's jewelry is found with an orphan, the victim's daughter and nephew share family secrets.

After Su Wenli witnesses the sudden death of a gossip columnist at a nightclub, she uncovers his history of infidelity and blackmail.

After the police find the murder weapon in the nightclub singer’s dressing room, Su Wenli goes to her friend’s house for answers – and uncovers a shocking secret.