Reminiscent of a small wave of psychological thrillers that were released at the end of the nineties and beginning of the naughties (Ringo Lam’s Victim, Law Chi Leung’s Inner Senses and Double Tap come to mind), Dante Lam’s That Demon Within follows a troubled cop (Daniel Wu) who one night offers to give his O- type blood to save a severely wounded man (Nick Cheung), who turns out to be the leader of a vicious gang nicknamed the “Demons” because of their colourful demon masks and cruelty. Their paths are to cross again to disatrous consequences, as the cop start to struggle with deep-buried mental issues and violent urges while the robber locks horns with his double-crossing gang.

This is a tremendously confident film. Dante Lam, who has been on a critical and box-office roll for the past 6 years, makes superb use of every trick in the book to convey psychological torment and collapse : Patrick Tam’s editing is razor sharp, Kenny Tse’s photography is strikingly in-your-face (for instance, sudden red lighting signal Daniel Wu’s violent schizophrenic fits, a trick so obvious and literal it actually works perfectly), and Leon Ko’s masterful score is a bold and propulsive mix of tribal, electronic and orchestral influences, all geared towards maximum expressivity and drive.

(the following paragraph contains some light spoilers)

Too bad then, that the script is a bit of muddle, relying too much on dimestore psychology, thudding coincidences and the worn-out reveal that some things you see are actually only in the character’s head (!). Still, the aforementioned directing mastery keeps the film on its enjoyable tracks, and a superb cast does a lot to sell the more trite plot turns : Nick Cheung projects a startlingly evil and sardonic presence, Daniel Wu gives perhaps his best performance so far, conveying the psychological unrest of his character as not just scary, but first and foremost, heartbreaking. The supporting cast is fine, with Dante Lam’s lucky charm Liu Kai Chi on top form and less over-the-top than usual, and while Andy On is sorely underused, Dominic Lam provides the film with a moral center, though even his driven Senior Inspector can’t escape the film’s deadening message, that evil lurks within everyone.

Long Story Short : While That Demon Within is unfortunately undermined by the dimestore psychology its script too often resorts to, it is nevertheless an enjoyable thriller, directed with tremendous flair and superbly acted. ***1/2