What, exactly, to make of Lucy? It's totally nuts. It's surprisingly introspective. It's patently ridiculous. And it is thoroughly entertaining.

Scarlett Johansson plays the titular character, a party girl who for reasons I'm not sure are ever stated, is studying in Taipei, Taiwan. The film wastes no time putting her in jeopardy: an extended argument with her boyfriend over his request to have her deliver a mysterious suitcase to a Korean businessman named Mr. Jang (Oldboy's Choi Min-sik) rapidly leads to her enslavement as a drug mule, as Jang turns out to be a ruthless gangster.

This drug, it should be noted, is a synthesized version of a powerful chemical called "CPH4". Sewn up in Lucy's stomach, when the drug starts leaking into her body, it grants her a wide array of superpowers.

This entire plot device is based on the well-known saying that human beings use only 10% of their brain capacity, so writer/director Besson essentially ponders what would happen if one of us – say, Scarlett Johansson – got a chance to tap into all 100%. Needless to say, Lucy doesn't just become ten times smarter. She essentially turns into Dark Phoenix.

Morgan Freeman costars as a neuroscientist who serves no other purpose than to voice Besson's thoughts about the human mind, and otherwise act as a sounding board for Lucy as she undergoes her dramatic transformation. In-between action set pieces (and sometimes right in the middle of them), Freeman's calming presence allows Besson to wax philosophical about what we're doing here, what knowledge is, how the universe works, and so on.

Lucy is an unexpected thriller/art film hybrid. But does it work? Well, it depends on whether you think Besson's ideas have merit or if it's all just pseudo-intellectual blarney coming from the mind of an armchair scientist. It also depends on whether you can stop asking yourself – as I could not – "So if Lucy can do this, then why can't she do that?" Some people will find Lucy profound; its cult status is already a lock. Others will shrug it all off as a bunch of silly nonsense not worth serious thought.

But the action is good, Johansson is great – it's irresistible to see a sort of continuum between her character here and those in her other recent sci fi films Her and Under the Skin – and at a brisk 90 minutes, Lucy doesn't wear out its welcome, even if it may leave some audience members baffled. You might love it. You might hate it. It's worth catching in either case.