Catch the Killer.

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.