Episode 1 recap: Abandoned building discovered a female corpse.

Three young individuals gathered for a meal in the abandoned building and started playing around, but they were startled when they discovered a dead body. The criminal investigator arrived at the scene, and the forensic examiner determined that the deceased was approximately sixty years old, with multiple knife wounds and a broken neck. The exact cause of death would require further autopsy. Xiao Yi was browsing watches at the antique shop nearby, and the shop owner mentioned that Xiao Yi frequently came around and treated the shop as a practice ground. The owner asked what kind of watch Xiao Yi was looking for.

Xiao Yi remained silent. Xiao Yi received a phone call and hurriedly came over. Gong Zilin came to pick up Xiao Yi and brought him inside. Forensic examiner Yao Shu Bei noticed Xiao Yi and appeared somewhat surprised. Xiao Yi instructed the others to investigate the nearby surveillance cameras, particularly to check for any three-wheeled vehicles or motorcycles. Gong Zilin found it strange, but Xiao Yi explained that large vehicles cannot enter this area, so three-wheeled vehicles and motorcycles would be the most convenient. Xiao Yi went outside to inspect and indeed found the tracks of a three-wheeled vehicle on the ground. Xiao Yi reported to Director Li, who acknowledged that Xiao Yi came here to investigate his mentor's case. Director Li stated that they welcomed the investigation but emphasized that it must be conducted with permission from higher authorities.

Captain Lu Guoxun also arrived, and Director Li asked him how he wanted to arrange Xiao Yi. Captain Lu expressed that he had heard about Xiao Yi's observations at the scene today and thought they were excellent. He decided to entrust Xiao Yi with full responsibility for the case. Gong Zilin informed Xiao Yi that there were no surveillance cameras near the abandoned building and no one had seen any three-wheeled vehicles or motorcycles passing by.

Xiao Yi and the others entered the forensic room, where Yao Shu Bei explained that the deceased had a total of eight knife wounds, with one piercing the heart as a fatal injury. The victim's anus was torn, indicating sexual assault, and traces of lubricant were detected internally. However, no semen was extracted, suggesting the violation occurred after death. The injuries on the neck showed no signs of vital reaction, indicating they were inflicted postmortem. Yao Shu Bei also mentioned that there were no traces of the perpetrator found on the victim's body, indicating that the body had been thoroughly cleaned.

Xiao Yi and the others were discussing this case. Xiao Yi found it very strange that the deceased had so many knife wounds, which seemed like a crime of passion. However, the fact that the body had been thoroughly cleaned after death indicated that the perpetrator was meticulous and had counter-surveillance awareness. These two behaviors were contradictory. Some of the injuries on the body seemed to have been caused by being stuffed into a suitcase, but there were also broken bones in the arm, suggesting prior experience of violence, possibly domestic abuse. The identity of the deceased has been confirmed as Wang Suhua, and she has a son named Gao He. It is highly suspicious that Gao He did not report his mother missing for a week.

Liang Dong Ni contacted Gao He's wife, Hao Na. Hao Na claimed to have been away during this period and had just returned for questioning. She mentioned that Gao He got into a fight and needed money for compensation, asking her to borrow money. Gao He is currently unreachable because he is in hiding to avoid debt. Xiao Yi discovered bloodstains in the house and intended to collect them for testing.

Xiao Yi took a taxi back, and the driver's name was Bai Zhe. After returning, Bai Zhe removed the license plate from the car and stared at the monitor. A girl wrote a suicide note and jumped from upstairs. Captain Lu and his team arrived to investigate, and upon learning that the deceased lived in 603, they went up to inspect the place. Currently, there are no footprints of a second person found in the room, nor are there any signs of a struggle.

The data has also been analyzed, and the distance the deceased fell matches the characteristics of a natural fall. It now appears to be a suicide, but Captain Lu feels that something is still not right. There are numerous designer bags in the deceased's home, and there is an unopened package containing another designer bag. Captain Lu ordered an investigation into the deceased's social relationships.