Set in a remote and bleak border post during the 1970s cold war between China and Russia, this is a study of boredom and a gradual thawing of relations between opposing guards which leads to a bizarre border incident.

Originally living a happy and stable life, things have become clouded for rich heiress Ye Shuang (Qin Lan) after the unexpected disappearance of her husband Ling Feng (Archie Kao) and daughter. After consulting with her father Ye Cheng (Simon Yam), Shuang decides to call the police, where she re-encounters her ex-boyfriend, Yao Jie (Gordon Lam). During the investigation process, Jie finds this million-dollar ransom kidnapping case to be a misty mystery. Specializing in investigating by starting from minor details, he targets Cheng as a potential suspect. At this time, Cheng's activities has also become suspiciously strange. When the mystery seemed to have dispersed, Cheng dies from an accident. At this time, clues from a murder case that took place 20 years ago begins to surface. Behind the mysterious kidnappings lies the ulterior motive.

The municipal police receive a report of the discovery of two corpse fragments less than 300 meters away from the river. Through investigation, they discover that the murderer was accidentally killed when he tried to sexually assault Su Baoyan. While Su Meiyan, Baoyan's sister, and her boyfriend Gao Xiong exhaust all means to protect Baoyan in their own way, they end up spiraling deeper and deeper into the abyss.