Good and evil exist in every one of us; which of the two is dominant in any particular person all comes down to our thoughts and decisions. Directed by Dante Lam, That Demon Within explores how evil can change a person's life.
Policeman Dave Wong (Daniel Wu) unwittingly saves a violent gang leader Hon Kong (Nick Cheung) by donating blood to him. Hon used to be a policeman, but is now wanted for the crimes he committed, and the lives of fellow police officers he took.
The accident turns Wong's world completely upside-down: he now finds it difficult to decide what is right and wrong. On the one hand, saving a life is always the right thing to do, but Wong doesn't want to save a murderer.
To set things right, Wong determines to kill Hon. He sets about tracking down the criminal and his supporters, but in the process harms many innocent people as well.
American-born Wu gives an outstanding performance as he takes on his darkest character to date . And Lam is always good at delivering the guns blazing thrills of a horror and action film.
The storyline gets a bit complicated as it jumps back and forth between Wong's imagination and reality. But the excitement does not disappoint.
Film contains scenes of violence and coarse language.