At the scene of the third secret room murder case that Ling Yan took over, she found the same strange symbol as the previous two cases - an incomplete five-pointed star painted with the blood of the deceased. This forced her to put aside her grudge against Shen Ci and dial the number she had not contacted for three years. Shen Ci was once the youngest criminal psychology consultant in the police force, but suddenly resigned due to a controversial case. Now she appears at the crime scene as a "freelance researcher". She crouched in front of the symbol and sneered: "Captain Ling still only looks at the surface." The first cooperation between the two was tense. Ling Yan was disgusted with Shen Ci's "empathic analysis" of the murderer, while Shen Ci mocked Ling Yan for being trapped in inherent thinking. Just as they were arguing about the meaning of the symbols, the fourth case occurred. The deceased was actually a key witness in the controversial case that year. In addition to the five-pointed star, there was also a note saying "Repay Debt" on the scene. Ling Yan found out that the deceased had met Shen Ci before his death, but when questioned, he was asked in return: "Aren't you curious, why did I leave back then?" As the investigation deepened, they found that all the deceased were related to the unjust case three years ago, and the five-pointed star symbol was the last mark left by the victim back then. When the murderer targeted Shen Ci, Ling Yan stood in front of her, only to realize that she had already fallen in love with this "enemy" through repeated quarrels and tacit understandings. Shen Ci's words "I never doubted you" made the two finally choose to hold each other's hands in the whirlpool of truth and emotion.
Purpose: There is only one truth