Episode Summary
Detectives Xu Xiao and Lin Guoqiang learn from Zhao Zhengru's mistress that their relationship was non-physical due to Zhao's health issues. Meanwhile, archaeologist Chen Nan discovers from developer Manager Pang, Zhao's former classmate, that Zhao had a promiscuous past and once angered a boyfriend who assaulted him. Chen Nan also identifies runes found on a tortoise shell as part of an immortality ritual, though incomplete. Following a lead from a musician Zhao knew, the police track Wang Bingde's apprentice, Cui Haitao, to his restaurant. Cui leads them to Wang's former residence, where Lin Guoqiang collapses upon seeing a scene identical to his daughter's murder scene. Xu Xiao learns from Shi Shu that Lin's daughter was killed years ago by murderer Zhou Jiahei after Lin refused to stop investigating him.

Spoiler Alert
"Hanging Mirrors" Episode 14 Recap & Spoilers: Digging Up Dirt and Dark Pasts
Alright, so picking up the investigation into Zhao Zhengru's death, our detectives Xu Xiao and Lin Guoqiang track down Zhao's mistress. At first, she plays it cool, all calm and collected. But the moment they drop the bomb that Zhao Zhengru is actually dead, her composure cracks, and she gets visibly nervous. Lin Guoqiang really puts the pressure on, and she finally spills the beans about their arrangement. Get this: despite being his "mistress," they never actually had a physical relationship. Apparently, Zhao Zhengru had some health issues (cough impotence cough) and was seeing her more for the... well, stimulation and thrill of it, hoping it might help his condition. Interesting, right?
Meanwhile, Chen Nan is busy doing her archaeology thing at an ancient tomb site. Who shows up but a real estate developer, Manager Pang. Turns out, Pang's company found this tomb while prepping a construction site. Even though the archaeological work on the tomb itself is done, he needs Chen Nan's official sign-off before his company can resume building. While looking over the paperwork, Chen Nan spots that Pang's company has ties to Zhao Zhengru's company – and even crazier, Pang and Zhao were classmates! Naturally, Chen Nan, ever the opportunist for intel, starts asking questions.
Pang dishes some juicy gossip about Zhao's college days. Apparently, Zhao was quite the player, leaving a trail of broken hearts ("romantic debts," as they put it). Things got really messy in his senior year when he was caught red-handed with someone's girlfriend. The angry boyfriend didn't hold back – he reportedly ambushed Zhao with pre-made ice blocks (ouch!) and beat him up pretty badly. Zhao was too embarrassed to even call the cops. Pang also mentions Zhao had a thing for a certain musician, but confirms nothing physical happened there either.
Chen Nan knows this info could be gold. Thinking fast, she tells Pang she needs more time to review the contract, holding onto it as an excuse to stay in touch. As soon as Pang leaves, she rushes to Xu Xiao and Lin Guoqiang with the news.
Xu Xiao, ever the pragmatist, isn't too impressed with the college gossip, thinking it's not directly helpful for solving the murder. Instead, he shows Chen Nan a photo of some runes found inscribed on a tortoise shell. Chen Nan, being the expert, immediately recognizes them – they're related to achieving longevity or immortality! But, she points out, it's only half of the inscription. To understand the complete "method" for long life, they need the other part.
This immortality angle gets Xu Xiao and Lin Guoqiang thinking. They decide their next move should be tracking down that musician Zhao Zhengru was apparently fond of.
They find the musician, who confirms she hasn't had contact with Zhao in a long time. However, she does recall Zhao taking her to an underground antique/artifact exhibition hosted by a guy named Wang Bingde. She actually has a pretty positive impression of Zhao, remembering him as a gentleman who never pressured her into anything she didn't want to do.
But then, she drops a crucial piece of information: Zhao once took her to a restaurant owned by Wang Bingde's apprentice, Cui Haitao. And here's the kicker – the restaurant's location corresponds to the Southwest direction, the exact "favorable direction" Chen Nan had mentioned earlier based on her expertise! Bingo.
Xu Xiao immediately leads a team to Cui Haitao's restaurant, setting up surveillance, hoping to nab Wang Bingde. After a long wait with no sign of Wang Bingde, they decide to confront Cui Haitao directly, cornering him in a deserted alley. (The source text mistakenly says they cornered Zhao Zhengru here, but contextually it must be Cui Haitao).
Initially, Cui plays dumb, claiming Wang Bingde was just some customer who visited a few days ago. But Xu Xiao isn't buying it and calls him out, revealing they know he's Wang Bingde's apprentice. Caught in the lie, Cui Haitao has no choice but to cooperate and leads the police to a place where Wang Bingde had been staying.
As they search the premises, disaster strikes. Lin Guoqiang walks into a room and freezes. The scene inside is set up exactly like the scene where his own daughter was murdered. The shock is too much; he's overwhelmed, clutches his chest (likely a heart attack or severe panic attack), collapses, and has to be rushed to the emergency room.
Seeing Lin Guoqiang's extreme reaction, Xu Xiao realizes his partner has been hiding something significant. He makes a call to their old colleague, Shi Shu, demanding answers about Lin's past. Shi Shu finally reveals the heartbreaking truth: years ago, Lin Guoqiang investigated a brutal dismemberment case. The killer, Zhou Jiahei, first tried to bribe Lin to drop the investigation. When Lin refused, Zhou Jiahei kidnapped Lin's young daughter, trying to force him to back off. Lin Guoqiang, dedicated to his duty, didn't stop investigating. In retaliation, Zhou Jiahei murdered his daughter.
Whew. So, Lin Guoqiang's personal trauma is directly tied to methods potentially being used in their current case, possibly by Wang Bingde or someone connected to Zhou Jiahei. This just got incredibly personal and dangerous for him. What a cliffhanger! We'll have to see how this devastating connection impacts the investigation and Lin himself in the next episode.