Man's unhealthy relationship with technology takes a sinister turn in Wally Pfister's ham-fisted sci-fi thriller, which imagines the consequences of an artificial intelligence running amok in the digital realm.

The high-brow concept of Jack Paglen's undernourished script is at odds with the whizz-bang pyrotechnics that director Pfister is asked to deliver in the muddled second act, ultimately starving the film of jeopardy.

Characters are poorly developed and the line between the supposedly evil computer and valiant human rebels is blurred to the point that we couldn't care less if our entire species is wiped out. Total oblivion would be sweeter than another 20 minutes spent in the company of a morose Johnny Depp and his co-stars.

Transcendence opens in Berkeley, California in the aftermath of a global blackout.

"The internet was meant to make the world a smaller place but it actually feels smaller without it," muses Dr Max Waters (Paul Bettany).

The narrative rewinds to the same location five years earlier, where Dr Waters's good friend Dr Will Caster (Depp), a pioneer in the field of artificial intelligence, lives with his wife Evelyn (Rebecca Hall).

They are at the forefront of a scientific vanguard, which hopes to create a machine with sentience.

Extremists called R.I.F.T. (Revolutionary Independence From Technology) oppose this advancement and shoot Will with a polonium-tainted bullet.

Doctors give Dr Caster a month to live so Evelyn suggests her beau continues his work by uploading his mind to a super-computer.

Dr Waters urges caution but Evelyn ignores his warnings, desperate to cling onto her husband.

R.I.F.T. leader Bree (Kate Mara) is powerless to stop Will making the leap into the digital abyss and when Evelyn uploads him to the internet, he infiltrates every hard drive on the planet.

As Will's thirst for knowledge intensifies, Dr Waters joins forces with fellow academic Joseph Tagger (Morgan Freeman), FBI agent Donald Buchanan (Cillian Murphy) and military man Colonel Stevens (Cole Hauser) to create a virus that will corrupt Will and protect mankind from his insidious influence.

Transcendence begins promisingly, setting out Will and Eve's utopian vision of cutting-edge technology to heal the planet and eradicate disease.

Once radioactive isotopes are coursing through the central character's bloodstream, screenwriter Paglen struggles to sustain dramatic momentum and the final hour unfolds at a pedestrian pace that makes the running time seem closer to three hours than two.

Depp's lifeless performance suggests a robotic doppelganger was hired to take his place while Hall and Bettany are tortured and tearful, wrestling with murky questions of morality that seem beyond the film's flimsy grasp.

If the end point - a world starved of electricity and gadgets - halts screenings of Pfister's film then perhaps there is method in R.I.F.T.'s muddled madness.