Episode Summary
Detectives Wei Jie and Liu Ziming go undercover in a rundown basement to surveil murder suspect Shen Fu. After an uncomfortable four-day stakeout, they apprehend Shen Fu and his crew. Through interrogation, particularly of Shen Fu's youngest accomplice Kanzi, they learn Shen Fu murdered Jin Di out of jealousy and forced his men to participate. The case is closed, but Liu Ziming faces hostility from the victim's parents. The episode then jumps to 2002, showing Liu Ziming dating Fang Tingting. Wei Jie heroically defuses a bomb situation, leading to his transfer to a special task force. The episode ends with Liu Ziming, Liu Yang, and Cao Lei responding to a new homicide case.

Spoiler Alert
The Stakeout from Hell
So, our guys Wei Jie and Liu Ziming finally tracked down the murderer, Shen Fu, to some grimy basement apartment. Wei Jie, ever the dedicated cop, decides the best way to catch this guy is to get up close and personal. He actually gets approval from Captain Huang (Captain Huang) to rent a room in the same basement for a stakeout. Captain Huang, worried about Wei Jie going solo, insists he take backup. With the team stretched thin, Wei Jie picks Liu Ziming and also manages to borrow Wu Hai from Zhao Dahai's team. Before they head into the delightful conditions of their new temporary home, Wei Jie tells Liu Ziming to run home and let his family know he'll be off the grid for a bit.
Liu Ziming rushes home only to find his dad, sister Liu Ziqing, and his brother-in-law in the middle of making dumplings. Turns out, it's his dad's birthday – talk about awkward timing! His brother-in-law, always up for some friendly competition, tries to get Liu Ziming to wrestle. But Liu Ziming, antsy to get to the stakeout, gives a quick, non-committal effort, grabs a few clothes, and makes a hasty exit, leaving his sister's pleas to stay for dumplings unanswered. Duty calls, you know?
Before meeting up with Wei Jie, Liu Ziming swings by Man Tianxing Education to say a quick goodbye to Fang Tingting. She’s out, but a call reveals she’s only about twenty minutes away. Liu Ziming, however, is too impatient to wait and just leaves a gift for her with the doorman.
Then, it’s stakeout time. Wei Jie, Liu Ziming, and Wu Hai settle into their new, less-than-glamorous accommodations. The basement is dark, damp, and crawling with all sorts of characters. People are cooking in the hallways, so our detectives are living on instant noodles. The shared bathroom is so rank that Liu Ziming, bless his heart, actually takes it upon himself to clean it.
The Takedown and a Singing Canary
Four days drag by with no sign of Shen Fu. Then, while Liu Ziming is out on an instant noodle run, he spots their guy! Shen Fu and four of his cronies are heading back to their basement hideout. Liu Ziming immediately alerts Wei Jie, who calls for backup. Just as Shen Fu and his crew of five try to slip away, Wei Jie confronts them, gun drawn. The rest of the police team arrives in moments, and Shen Fu’s little gang is quickly apprehended. Captain Huang is full of praise for Wei Jie's efforts.
Wei Jie starts interrogating Shen Fu, but he’s not cooperating. So, Liu Ziming tries a different tack with Shen Fu's youngest goon, a kid named Kanzi. Liu Ziming lays on the charm, reason, and a bit of emotional blackmail about his future. Then Wei Jie bursts in, playing the intimidating bad cop, and Kanzi completely crumbles, spilling all the beans.
Here’s what went down, according to Kanzi: Shen Fu and his crew were at a karaoke club called "Mermaid Palace" (Renyu Gong). Shen Fu got into it with a guy named Jin Di. Things escalated, and Shen Fu lured Jin Di to a nearby riverside, ambushed him from behind, and stabbed him multiple times. Then, in a truly chilling move, Shen Fu forced Kanzi and the other guys to each stab Jin Di three more times. Once Shen Fu learns that Kanzi has confessed, he admits to his actions too. Apparently, Jin Di's parents were well-off (doing business in Korea), and Jin Di was known for flashing his cash and buying things for his "brothers." Shen Fu had been stewing over this, got drunk, and decided to kill him. He even tells them where he hid the murder weapon.
Case Closed, but the Drama Continues
Wei Jie and his team recover the weapon, and the case is officially closed. Wei Jie offers to treat everyone to a celebratory meal. However, Liu Ziming makes an excuse and leaves early. He heads directly to Jin Di's parents to inform them the case has been solved. You’d expect gratitude, but instead, Jin Di's mother (Jin Mu) flies off the handle and yells at Liu Ziming, and Jin Di's father (Jin Fu) angrily kicks him out. Rough day for Liu Ziming. Understandably upset, he goes to his old wrestling team to blow off some steam.
Later, Liu Ziming plans to meet up with Fang Tingting. But Wei Jie, who seems to have a sixth sense about his team's personal lives, already knows Liu Ziming and Fang Tingting are an item and invites her to join them all for a barbecue, effectively crashing their plans.
New Year, New Dangers
Then, we jump forward to 2002. Liu Ziming and Fang Tingting are officially a couple, and he takes her to meet his sister, Liu Ziqing, who absolutely adores Fang Tingting. Just as Liu Ziming finishes ordering food at a restaurant, he gets a call from Wei Jie – there's an urgent situation at a crime scene. He has to ditch the meal and rush off.
The scene is tense: a perpetrator has taken a hostage inside a van and is armed with explosives. Wei Jie, cool under pressure, manages to sneak up behind the van, disable the explosives by pulling the fuse, and then aims his gun at the culprit. The rest of the officers then storm the van, subdue the bad guy, and safely rescue the hostage.
Liu Ziming is incredibly impressed by Wei Jie's heroic actions and excitedly calls Fang Tingting to tell her all about it. Wei Jie's bravery doesn't go unnoticed by the higher-ups either; the city bureau assigns him to a special task force. Wei Jie packs his bags to leave, and Liu Ziming is sad to see his mentor go but knows there's nothing he can do.
Just as Liu Ziming, Liu Yang, and Cao Lei are feeling a bit lost without Wei Jie, they get a call: there's been a homicide at the Garden Community (Huayuan Xiaoqu). No time to dwell – they immediately head to the new crime scene. And that's where Episode 4 leaves us hanging!