Jon Man (Jay Chou) is a police officer whose life abruptly changes when an operation to escort a criminal scientist and his family into police custody goes horribly wrong. Not only is Jon's wife, a fellow officer, killed in the chaos, but Jon ends up with a bullet in his brain that will kill him in two weeks. He checks himself out of the hospital and returns home, only to have another bombshell dropped on him by his mother: it was not his father who left when Jon was young, but she and Jon who left his father, and more importantly, his brother, Yeung. When Jon goes to visit them, he discovers that Yeung (Nicholas Tse) is not only a criminal, but that he's working for the same people who killed his wife and shot him in the head.

Frankly, I don't know why the film is called The Viral Factor. Yeah, sure, a deadly mutation of a virus is stolen, and most of the characters are desperate to get it back, but the real story here is about family -- not just Jon's brother, but also his father (Kai Chi Liu), his mother (Elaine Jin) and his niece, Champ (Crystal Lee). What's refreshing about The Viral Factor is that it doesn't bore the audience with predictable nonsense about Jon and Yeung judging each other's opposing lifestyle or bickering over their parents (or even linger on the revelation that they're actually brooooothers), but instead has the characters work together as they both try to outrun dirty cops and vicious criminals. Both men are too short on time to waste any bickering, and their teamwork and pursuit of each other is all to learn more about what they missed in the 20+ years they've been apart. The script, by Lam and Jack Ng, provides simple but compelling scenes for Jon's mother and father that outline their hindsight about their choices, and a powerful back story for Yeung is nicely underplayed.

Lam also packs the film with fast-paced, exciting action sequences that hint at an over-the-top sensibility without clashing with the tone of the rest of the film. Bullet trails help define the geography of one character in relation to another in shootouts, and the editing by Chung Wai-Chiu is quick without being choppy. Highlights include a high-impact fight inside the confines of an overturned van (with one character whose hands are bound), a brief but extremely memorable car stunt involving a cafe, and a car chase through a crowded shopping center that ends unexpectedly. Lam even scores big with simple, old-fashioned stunts, like a rope swing across an open cargo bay, although a helicopter chase staged like a car chase might be a little too silly.

Some of the beats near the end of the film still work their way up into the stratosphere with melodramatic pyrotechnics, but most of these moments are spiked with a brutal, take-no-prisoners violence that brings the audience back down to earth. Lam isn't afraid to throw his characters through the ringer, but he dishes it out in measured doses so that the viewer doesn't become desensitized to each new punch or bullet. The story of The Viral Factor sounds simple and familiar, but Lam's film is a perfect example of how a little effort into showing the audience something different and a strong understanding of technique can elevate a somewhat formulaic action movie into something more resonant.

The Blu-Ray
The artwork for The Viral Factor faintly suggests a different movie, one that would pit Jon against Yeung in some sort of good-vs.-evil grudge match. No idea if Well Go USA thinks that will sell more Blu-Rays or what, but personally, I find the actual story of the film more interesting. The disc comes in an eco-friendly vortex case with a cardboard slip featuring the same artwork as the actual paper cover, and inside the case is a flyer advertising a couple of Well Go's other Blu-Rays.

The Video and Audio
The Viral Factor's 2.35:1 1080p AVC presentation runs a little hot. Whites and other bright spots frequently burn out, and saturation still seems overcooked even in scenes where the image is not intentionally altered. Black levels are decent but a bit inconsistent, but fine detail is fantastic. A strong, but imperfect HD video presentation.

A Cantonese DTS-HD 5.1 Master Audio track leaves less to be desired. Powerful gunshots, massive crashes and explosions, and even a thumping, thundering club scene provide fantastic opportunities for engaging, rich audio. Dialogue is sharp as a tack. Although the picture is a little lacking, the sound is basically flawless. (The Viral Factor also might be an interesting compromise for those resistant to subtitles, since 35 to 40% of the movie is in English.) An English 5.1 DTS-HD MA dub is also provided, along with English and Cantonese Dolby Digital 2.0 stereo tracks. English subtitles round out the language options.

The Extras
A making-of featurette (14:40) and interviews with the cast and crew (34:37) are included. The featurette is a nice overview of the production (and not exhaustiningly overlong like some Asian making-of extras), but the interviews are a little dry and promotional in nature.

Trailers for The Courier and Legendary Amazons play before the main menu. An original theatrical trailer for The Viral Factor is also included.

Conclusion
The Viral Factor is a solid thriller. Although it probably could've lost five to ten minutes from the running time, it should satisfy anyone looking for an action movie with a little more dramatic meat on its bones. Recommended.