Odor analyst Wen Shiyan has an extraordinary gift of smell - he can identify more than 300 trace odor residues, from rain minerals on the suspect's clothes to hand cream fragrance residue on the murder weapon. He can even restore the sequence of the crime through the "attenuation trajectory" of the smell. A series of seemingly unrelated disappearances started with a wisp of "burnt sweet cold fragrance" that only he could detect: the same out-of-print perfume was hidden in the homes of the missing persons, rare Himalayan rock salt particles remained at the crime scene, and even the victim's last smell was mixed with subtle apricot. Ren's suffering... When the criminal investigation team was stuck in the deadlock of "no witnesses, no surveillance, and no physical evidence", Wen Shiyan used smell as the key to dismantle the maze of crimes: the level of fragrance corresponds to the modus operandi, the concentration of the smell estimates the residence time, and even the differences in the smells absorbed by different materials point to the real culprit. He not only has to fight against the physical pain of his overloaded sense of smell, but also has to convince the old-school criminal police who doubt that "smell cannot be used as evidence". In the process of chasing the murderer, he has to face the secret connection between this "cold fragrance" and his childhood disappearance case. Every smell is an unheard cry for help, and every sniff is an adventure closer to the truth. See how the "smell detective" uncovers the tangible truth of sin in the invisible world of smell.
