Lu Shi, the young leader of the "Blade" team of the Criminal Investigation Detachment of the Municipal Public Security Bureau, is known for his calm and sharp style of solving cases, but he has become increasingly silent after an unsolved case three years ago. The arrival of trainee police officer Su Wan broke the silence of the group - this seemingly quiet girl who always notices the details that others ignore, not only has an outstanding talent in criminal psychology, but also seems to have a secret connection with the unsolved case three years ago.
