In a future city where emotions can be extracted, stored and traded, a strange thief who specializes in stealing "sadness" appears. Lin Jing, a top emotional tracer, was hired to investigate. He can read the emotional imprints remaining on items. However, when he got deeper into this bizarre theft case, he found that all the clues pointed to his own dusty past and the most painful memory that had been forcibly stripped away. Is he pursuing the truth or the lost self?
