保險經紀葉永信〔陳家樂 飾〕被神秘客戶指定跟進保單，在上門拜訪時，親眼目睹客戶兒子吊死在半空，正直的他認定客戶為詐取保險金而濫殺兒子，決心向這對夫婦——朱重德〔黃秋生 飾〕和沈子玲〔林嘉欣 飾〕展開追查，憑一己之力將犯人繩之於法，沒料這顆正義的心剛好是敵人反擊的籌碼。
The Road to Hell Is Paved with Good Intentions…
Insurance agent Sean is called to visit Tak and Ling’s home to follow up on a life insurance policy. When he goes into the bathroom, he is shocked to see their son’s corpse hanging above him.
When he sees Tak’s cold, emotion-less response to the child’s death, Sean – a righteous and kind-hearted man dedicated to his job – begins to suspect Tak and Ling may have murdered his son for the insurance money. When the police conclude that there was no foul play at work and the insurance claim is approved, Sean decides to lead his own investigation instead.
However, as Sean becomes obsessed over Tak’s guilt, his kind nature is used against him by the real perpetrator. Sean begins to receive one disturbing threat after another at home, and the people around him are put in danger. Before Sean finally uncovers the shocking truth, the hunter becomes the hunted as the real killer forces Sean into a psychological battle of wills that sends him into the limbo between good and evil.