Derriere-numbingly long films may be all the rage but at a lean 89 minutes, Lucy, the new action thriller from Luc Besson, is all the better for bucking this Hollywood trend.

And with a kidnapping, killing sprees and questionable drugs thrown into the fray, there's certainly enough in that hour and a half to halt you from slipping out of the cinema.

Lucy (Scarlett Johansson) is a carefree student living in Taiwan, who is tricked by her new boyfriend Richard into doing his dirty work and carrying a briefcase, jam-packed with potent new drugs, into a hotel for him.

But there's no time for pleasantries here and before the concierge has greeted Lucy, Richard has been dispatched and Lucy is held hostage by the neighbourhood's merciless mob of local drug lords headed up by the unsparing Mr Jang (Choi Min-sik).

Waking up, Lucy discovers that the mob has taken the liberty of surgically implanting thousand of pounds worth of a deadly blue drug, CPH4, which increases the user's brain capacity, into her stomach.

And more than that, if the bright blue crystals leak, it will kill her.

But leak it does and Lucy, who is sent across the world as a drug mule, soon finds her brain working on disturbing new levels, signposted in the film with frequent updates on the percentage of brain capacity she's using.

As well as being hell-bent on exacting revenge on the mobsters, Lucy also busies herself by tracking down the eminent professor Samuel Norman (Morgan Freeman) in Paris who has spent decades researching the brain's potential.

In a deft twist to Johansson's role as a human-like operating system in Spike Jonze's Her, Lucy sees the actress' voice take on a lifeless tone, shedding personality and lightness as her brain's potential expands.

Much has been made of the film's neurological theory not stacking up, but scientific soundness isn't the mission here - entertainment is.

And while there are some rather odd moments - the flashes to a prehistoric Lucy, the strained conversation Lucy has with her mum and the missed opportunity to kill Mr Jang while she can - Lucy is nevertheless a punchy film, which demands your attention every minute of the way.