Way back when, Disney was one of the first studios to pioneer the use of CGI in its films with the 1982 cult hit 'Tron'. Fast forward 28 years and although Disney's a year or so late for the party, 'Tron: Legacy's stunning integration of 3D and plot puts it firmly on the crest of this technology's wave. It's just a pity no-one gave as much thought to the story as they did to the means of delivering it.

Sam Flynn (Hedlund), all angsty and aimless, is haunted by the disappearance of his father Kevin Flynn (Bridges, reprising his role from the first film) 20 years earlier. Only Alan Bradley (Boxleitner), Flynn's one-time business partner, is convinced that Flynn Snr is still alive. When Bradley receives a page from the phone in Kevin's old office, he suggests that Sam should go and investigate. In the building Sam discovers a secret room and a few strokes of a keypad later finds himself digitised and thrown headfirst into 'The Grid', a domain the older Flynn created in a quest to combine the physical world and the digital one.

3D effects, which up until this point have been used sparingly, now come into their own as Sam is hurled into a world he knows nothing about, and must battle with different 'programmes' made to look like people. After successfully navigating himself through his first test, Sam meets CLU 2 (also played by Bridges, albeit 20 years younger), who Sam thinks is his father but is in fact a programme spawned by Kevin when The Grid was in its infancy. Some years back CLU 2 sought control of The Grid and since then Flynn Snr has been trapped in exile and unable to return home. Rescued by Quorra (Wilde), Sam is finally reunited with his father and the stage is set for an almighty hoo-hah as to whether father and son will get home in one piece, or be stuck in their digital prison forever.

Visually, the audience's time in The Grid is as impressive as any 3D sequences they'll see, as architecture and the rules of physics are bent and re-imagined. Whereas many blockbusters now seem to tack on 3D as a finishing coat of paint, in 'Tron: Legacy' the effect is crucial to capturing the audience and keeping them involved. That's not to mention the film's score, and indeed a rather special cameo from French House duo Daft Punk, who know exactly when to add deft touches to scenes or conversely pump up the tunes when needs be, à la their first album 'Homework'. The older Bridges isn't half bad either, as the sagely computer hippy, spouting his Lebowski-esque musings of "That's bio-digital jazz man..."

So if all these things work, then why three stars? Well, characterisation, tension and story - what most of us go to the cinema in the first place to see - are all sadly lacking. Bridges, fine actor that he is, can only do so much. The film clocks in at just over two hours, and about five minutes and a couple of clichés are all we get to explain who these people really are. Action sequences, although a banquet for the eyes, leave you feeling unnourished because character development is so glaringly absent. And story? I've seen some silly storylines in my time - some real corkers - but as this film wears on the more convoluted it becomes, its overwrought conclusion taking the proverbial biscuit.

That said, 'Tron: Legacy's technical achievements are hard to ignore, as it brings the 3D medium further than before. Although its story may be somewhat flawed, there's more than enough here to justify warming a cinema seat over the Christmas holidays.

Padraic Geoghegan