If you've not heard of Park Chan-wook's Vengeance Trilogy then seriously, where have you been? Watching too many low-grade Hollywood movies I'll wager. Mind you, if your diet consists largely of Disney or Dreamworks fluff, then this is probably territory you'll want to avoid. Park's films make enthralling but sometimes supremely uncomfortable viewing. Sit down in from of one of them and you'll be taken to dark places, darker than you may be used to, and I'm not talking about the lighting. If screen violence makes you wince then I'd keep your shoes and scarf on, as you're likely to be through the door before the end of any of them. And if you like your endings happy and your character arcs by the book, then you are definitely going to have problems here. But if the timidity and repetitively formulaic nature of the Hollywood product leaves you yawning, if you yearn for films that are as challenging as they are cinematically thrilling, films that test moral and ethical boundaries and that have narratives that are genuinely and consistently unpredictable, then Park Chan-wook is your man.

There are no prizes for guessing the central theme that unites the three films, but vengeance here provides no cathartic release, no tidy resolution, and no real sense of justice. Vengeance destroys all those caught up in its execution, either physically or morally, and turns ordinary men and women into single-minded monsters. That violence is inflicted in often brutal fashion is par for the generic course, but although it can feel more extreme in Park's films, little of it is explicitly shown, the odd knife cut or spray of blood the exception rather than the rule. Park tends to put the actual act at a distance or cut away at the crucial moment, focusing our attention instead on the dreadful anticipation of its delivery and the suffering that always results. Revenge in a Park Chan-wook film rarely goes to plan and will not have you punching the air with your fist, but haunted by the effect its pursuit has for both victim and victimiser, and here it's possible to be both at one and the same time.

Many of those who have discovered the trilogy have done from its mid-way point, with the breakthrough success of Oldboy and its Grand Prix win at Cannes providing Park with a fan base far beyond his home shores. Seduced by its pace and visual pizzazz, some have looked less favourably on the other two films, but they shouldn't. The first of the three, Sympathy for Mr. Vengeance, may be more sedately paced but is beautifully developed and still packs a sledgehammer wallop, and although more straightforwardly plotted and dipping its toes in some dubious spirituality, Lady Vengeance is still a mother of a movie that boasts its share of surprises and moral discomfort.

I should point out that there is actually a fourth part to this trilogy, a shorter piece that is nonetheless absolutely in the style and spirit of the other films. Between finishing Oldboy and starting on Lady Vengeance, Park contributed a segment to the three-story film known in the west as Three... Extremes, a piece entitled 'Cut' that plays like the final third of a fourth Vengeance film, and even features Oldboy's Kang Hye-jeong in one of the main roles. Although not included in this otherwise busy box set, Three... Extremes is available on UK DVD from Tartan and has been reviewed here.

The other three films are already available individually from Tartan and the key question for anyone who already owns any or all of them is whether there are good reasons to purchase this new box set, or whether this is just a repackaging of goods that they already own. Well there's good news here, and quite a bit of it. One of the films has been remastered, another is being presented in an alternate version, and all three sport extra features not found on the previous releases, and quite a few of them. It's safe to say that hardcore fans of Park's films will want this box set even if they already have the three films, and if you have none of them yet then the set represents a very worthwhile purchase, although the more rabid Oldboy devotees are probably going to want the 2-Disc Special Edition as well, as it boasts a fair few extra features not included on the version in the Trilogy Box Set.

Although the news is largely good, there is one fly in the ointment on the Lady Vengeance disc that I'll address when I look at that film individually. There's a lot to cover on each of the discs, and it's taken me some considerable time to do so, a task I am still in the process of completing. The intention is to look at each film in both of its versions over the coming few days, to cover the film itself, the transfers and the extra features in detail to allow potential purchasers to chance to decide which version they want to splash out their hard earned on.

The links to the individual films and versions are in the ride-bar to the right of this review.