Episode Summary
Qin Wan discovers the Third Master was poisoned, confirming their theory of a revenge plot. The investigation into the well victims leads them to suspect Mrs. Yang's surviving daughter. A confession from the revived Third Master implicates a pawnshop and reveals the cruelty of the crimes. Clues like a colorful umbrella and the method used to move a heavy stone point to the maid, Cai He. It's revealed that Cai He and the Eldest Brother are lovers. The Eldest Brother confesses to the revenge plot to protect Cai He, but when Qin Wan exposes Cai He's own evil deeds, he attacks Qin Wan to silence her.
Spoiler Alert
Coroner's Diary: The Killer's Identity is Revealed in Episode 10
The web of deceit and revenge within the Qin family deepens as Qin Wan and Yan Chi close in on the truth behind the murders. The investigation takes a sharp turn when an attempt is made on the Third Master's life, not by his illness, but by a sophisticated poison.
The episode opens with Qin Wan discovering that the Third Master has been poisoned with "Jinshi" poison, a dose lethal to someone in his already fragile state. Yan Chi insists on keeping him alive to face justice, leading them to suspect that someone is trying to silence him permanently. Their theory points toward a revenge plot stemming from the "bodies in the well" case, believing a victim's family member has infiltrated the Qin household.
The investigation into the thirteen skeletons recovered from the well finally bears fruit. Qin Wan and Xu He identify the remains of Mrs. Yang, allowing her to be symbolically reunited with her daughter. It's revealed that after Mrs. Yang went missing, her husband died in a fire, but she had two daughters. One, now in her twenties, is the prime suspect who has likely entered the Qin estate to seek vengeance.
After being revived by Qin Wan's acupuncture, a delirious Third Master confesses everything. He admits that Butler Liu drugged thirteen young women and threw them into the well, all supplied by a local pawnshop that catered to his depraved tastes. He recounts how Mrs. Yang had followed her daughter to the mansion, begging to be let in with her. The Third Master's complete lack of remorse enrages Qin Wan. In the tense moment, she accidentally pricks Yan Chi's arm with a poisoned needle and hastily treats him.
A key clue emerges when Cai He, Old Madam Qin's most trusted maid, brings a brightly colored umbrella, an act Qin Wan finds uncharacteristically careless. Yan Chi realizes that the first step in the killer's plan was moving the heavy "demon-suppressing stone" in the purple bamboo forest. A search for Mrs. Yang's portrait proves fruitless, as all have been destroyed. However, they discover a secret room containing numerous paintings, including one commissioned by the Eldest Brother of a woman who is not his wife.
In the bamboo forest, Qin Wan deduces that the killer used the strength and flexibility of bamboo to move the massive stone, a task requiring two people. Acting on this, Yan Chi raids the Qingyuan Pawnshop to cut off the conspirators' communication. Meanwhile, Qin Wan learns from her Second Brother that the maid Lian Ye was killed in the same forest. Lian Ye, resentful of Cai He's promotion, had followed her and likely witnessed a secret meeting between Cai He and the Eldest Brother, leading to her murder.
The final pieces fall into place. Yan Chi learns that Mrs. Yang's husband was colorblind, a hereditary condition. This, combined with the garish umbrella, points directly to Cai He. As Qin Wan prepares to reveal the name to Yan Chi, Wan Tang alerts the Eldest Brother. He intercepts Qin Wan, confessing his love for Cai He and his plan to run away with her. He claims he is the one seeking revenge for her, as she had given it up for his sake. But Qin Wan confronts him with a horrifying truth: Cai He is far from innocent. She poisoned the Eldest Brother's wife with musk, intending to leave the third branch of the Qin family without an heir. Refusing to believe Cai He is malicious, the Eldest Brother attacks Qin Wan, attempting to strangle her to bury the secret forever.
