Shen Zhiyao, the useless intern mocked by the entire police station, recreates the complete scene of a series of red-dress murders from ten years ago overnight, stunning the whole city. The stone-faced team leader, Gu Yansheng, discovers that she can reconstruct the killer's methods, though they left no traces, through scent and light. Meanwhile, the forensic doctor's paintings, hidden away for five years; the janitor Chen Ya's strange behavior; and the evidence chief Lin Huai's altered records all point to a dark secret buried within the police station. When Shen Zhiyao begins dreaming of her mother's red dress fluttering in the rain, she finally understands: she is the true orphan left behind by that "perfect crime" all those years ago.
