Lucy

A popular urban legend is at the center of Lucy, namely the notion that humans are only able to access 10 percent of their available brainpower.

Of course, that concept has been widely refuted by science, and despite the efforts of French filmmaker Luc Besson (The Fifth Element) to introduce fictional neurological statistics into the argument, any attempt to perpetuate the myth is filled with speculation and ill-conceived theory.

Besson doesn’t claim his latest globetrotting science-fiction thriller is based on fact, of course, but its ambitions are muddled by a lack of conviction in its story of a mysterious woman forced to become a scientific guinea pig while caught in the middle of a drug deal gone bad.

Scarlett Johansson plays the title role, an American woman in Taiwan who is kidnapped and essentially forced to act as a mule for a Korean crime boss (Choi Min-sik) when she has a packet of a synthetic drug sewn into her stomach.

Nobody knows much about the substance she’s carrying until the packet apparently starts to leak, causing an overdose with a host of ramifications. Namely, the drug allows users to dramatically increase their brain capacity, even though it has some potentially deadly side effects.

Venturing to Paris, she seeks out the help of Professor Norman (Morgan Freeman), a biologist with extensive research into such matters. He tries to offer a scientific explanation for Lucy’s condition while she transforms from a helpless victim into a ruthless assassin bent on revenge.

As Lucy’s brainpower escalates, she gradually acquires several powers — presumably as a result of her increased intellect — including those of levitation, time travel, telekinesis, invincibility and omniscience. Apparently she knows a lot about weapons, too, which comes in handy.

Johansson brings a mix of vulnerability and strength to a role that ranks among the toughest of Besson’s tough-minded heroines over the past 20 years.

Besson keeps the pace lively and generates some powerful imagery through his stylish incorporation of special effects to suit his active imagination. However, his use of symbolism is more heavy-handed than profound, including his cutaways to wild-animal attacks and visual depictions of splitting cells and functioning human organs.

While the film manages some silly and superficial thrills, if Besson wanted Lucy to be more persuasive or intellectually challenging, he might have tried unlocking more of his brainpower in the process.

Rated R, 89 minutes.