Lin Ruohan has been lurking in the drug cartel for the fifth year. The guns and blood hidden in the dark are the background of her life. Only when she secretly visited Xu Zhixia at the medical school every month, and saw her wearing a white coat holding an anatomy atlas, did she feel that she was not swallowed up by the darkness - the girl she picked up from the orphanage and raised single-handedly was the "weak spot" she had to protect even at the risk of her life.
Xu Zhixia didn't know that the "Sister Lin" she relied on would use another name to walk through the dark alleys at night. All she knew was that she had to grow up to be a qualified forensic doctor quickly. When she was able to uncover the truth behind the corpse, she might be able to help Sister Lin, who was always "on business trips," find the wounds that she didn't want to talk about.
Until a bizarre corpse dumping case broke the balance: on Xu Zhixia's autopsy table, Lin Ruohan's undercover target was lying; Lin Ruohan's task list added a secret item of "protecting the forensic doctor from being involved". When the clues revealed by the corpse language point to the abyss where Lin Ruohan lurks, and when Xu Zhixia's scalpel is about to cut open the secret of her most trusted person, the two finally discover that they have long been each other's armor, and they are also comrades who must face the darkness together.
On one side is the undercover identity to be hidden, and on the other is the truth about the corpse to be pursued. At the junction of light and shadow, they use their own methods to piece together a sinful puzzle that spans many years, and also guard the unspeakable agreement about "guarding".
Purpose: patriotism, redemption, pure love