Episode Summary
"Si Jin" Episode 11 centers around Yu Qi's continued efforts to uncover Jiang Si's identity, using the Nightingale symbol as a test. Jiang Si seeks help from Liu Yan'er, leading to a confrontation where Yu Qi pretends to be unconscious, overhearing a crucial conversation about the Saintess. A street incident with the arrogant Princess Cui Mingyue further complicates matters, resulting in Yu Qi intervening and taking the princess away. Jealousy arises as Yu Qi witnesses Jiang Si's growing closeness with Zhen Heng. Jiang Si also arranges a marriage for her sister and takes steps to protect her brother.

Spoiler Alert
In Episode 11 of "Si Jin," the stakes are higher than ever. Yu Qi, despite capturing a suspect, fails to extract any useful information. Determined to uncover the truth, he decides to test Jiang Si using the Nightingale symbol. He uses a bow and arrow to shoot the symbol into Jiang Si's room at night. Jiang Si, recognizing the symbol and realizing that only Yu Qi knows about her Saintess Holy Maiden Totem, suspects a trap. Her immediate thought is to seek help from Liu Yan'er at the Tianxiang Pavilion.
Meanwhile, Zhen Heng, wanting to protect Jiang Si, starts practicing martial arts, although as a scholar, he struggles with the heavy weaponry. He also goes to great lengths to please Jiang Si, even injuring himself while gathering orchids for her.
Jiang Si's attempt to meet with Liu Yan'er is initially rebuffed. She returns home and enlists the help of her brother, Jiang Zhan. Together, they return to the Tianxiang Pavilion. The owner, recognizing Jiang Si's status, reluctantly agrees to the meeting, not wanting to offend Jiang Zhan. Just as Jiang Si's plan seems to be working, Yu Qi unexpectedly arrives, insisting on joining the meeting.
Jiang Si manages to get inside a private room with Liu Yan'er, claiming they need to discuss the art of incense. Yu Qi and Jiang Zhan are left outside, only able to observe through a screen. Liu Yan'er uses incense to knock out Yu Qi and Jiang Zhan. Jiang Si then lies, introducing herself as Zhao Yu from the Nightingales, and questions Liu Yan'er about the Saintess Holy Maiden Totem, asking if there are other ways to prove the Saintess's identity. Liu Yan'er reveals that a true Saintess can foretell the future and lead Southern Wu to prosperity. Unbeknownst to them, Yu Qi was only pretending to be unconscious and overhears their entire conversation.
Later, Jiang Si and Jiang Zhan are walking down the street when Princess Cui Mingyue rides her horse recklessly, causing chaos and casualties. Jiang Zhan confronts her, demanding an apology. Jiang Si, remembering a similar event from her past life that led to Jiang Zhan's death, panics. She desperately tries to de-escalate the situation, even kneeling to beg for forgiveness. However, Cui Mingyue's arrogance contrasts sharply with Jiang Si's willingness to humble herself for her family. The crowd begins to criticize Cui Mingyue, who, in a fit of rage, tries to run down Jiang Si with her horse. Yu Qi suddenly appears, stopping Cui Mingyue and taking her away.
Liu Yan'er, now suspicious of Jiang Si, starts investigating her. She discovers Jiang Si's shop and notices the similarity between Jiang Si's incense (made under the guise of Zhao Yu) and her own, leading her to suspect Jiang Si's true identity as the Saintess.
Cui Mingyue overhears her mother talking and learns that Yu Qi is a prince. She also hears about her father's connection to the Dongping Marquis Residence and questions Xu Momo about the person her father cares about.
Fearing Cui Mingyue's revenge, Jiang Si forbids Jiang Zhan from leaving the house for a month, for his own safety. Jiang Zhan initially refuses but eventually agrees for Jiang Si's sake. Jiang Si also hires Master Qin Feng to teach Jiang Zhan martial arts for self-defense.
Jiang Si, through Lady Zhen, arranges a successful match for Jiang Pei. Grateful for the successful matchmaking, Jiang Si thanks Lady Zhen, who openly expresses her admiration for Jiang Si and hints at a potential relationship between Jiang Si and Zhen Heng, leaving them with some private time.
To strengthen their bond, Zhen Heng asks Jiang Si to call him "big brother," which she does. Yu Qi arrives at the teahouse where Jiang Si and Zhen Heng are, overhearing their conversation and becoming jealous.