Su Cheng returns to his hometown after several years abroad to find his best friend Wang and old crush Lin Jing married and settled down. Cheng's memories of the city reflect a difficult childhood suffering from depression and frequent fights with classmates. Suddenly Wang is found brutally murdered in what police suspect to be one of a series of serial killings over cheating spouses. The killer kidnaps the cheating couple and tortures them before murdering one and leaving the other as a witne...