At the time it was the highest grossing production focused on a woman and became a box office success grossing eleven times its budget. Starring Scarlett Johansson, the movie was released in 2014, the year after another of her main movies, Under the skin, but I didn't see it until a few days ago.

Official Poster

In the film, Lucy (Johansson) is forced to transport a new drug, powerful and synthetic, in a bag inside her stomach, but after a violent incident the bag rips out, spreading the content inside her and flooding her blood system. From there, Lucy develops supernatural powers because her brain begins to increase the capacity of use until it reaches 100% use, becoming a lethal entity with extraordinary abilities, both physical and mental. She's not only capable of fighting and managing guns, or freeze people with the power of her mind but, as the movie moves forward, we realize she feels everything, she remembers everything and she suddenly knows evertythig.
The premise that humans only use 10% of our brain capacity is well known and has been the subject of multiple investigations. It's assumed that increasing the use of this capacity would imply a development of skills, but to know for certain what would happen when using a high percentage of the brain is to enter the field of the merely speculative.

With Professor Norman

At the beginning of the film, the first sequences intersperse the images of what happens with Lucy with others taken from the animal world (mice and mousetraps, hunts), the first two or three cause some laughter for its symbolism, but the abuse of the joke makes it boring. Another thing that didn't fully convinced me was that first, when she acquired those skills, Lucy started a violent revenge against the drug traffickers who intruded her into the matter. She looks like a whole femme fatale that first uses a weapon and then doesn't need it because her mind functions as such; but then the story derives, thanks to the intervention of Professor Norman (Morgan Freeman), towards the responsibility that Lucy has with humanity to bequeath all the knowledge that she has acquired so suddenly. There's a scene in which Lucy converses with Professor Norman and other colleagues of his and explains:

"Humans consider themselves unique, so they've rooted their whole theory of existence on their uniqueness. One is their unit of measure — but its not. All social systems we've put into place are a mere sketch: one plus one equals two, that's all we've learned, but one plus one has never equaled two — there are in fact no numbers and no letters, we've codified our existence to bring it down to human size, to make it comprehensible, we've created a scale so we can forget its unfathomable scale".

The explanation

And the she concludes: "Time is the only true unit of measure, it gives proof to the existence of matter, without time, we don’t exist". The scene is kind of tangled, it reminded me of the conversation with the architect in The Matrix, so it's possible that you may requiere see it several times. But once you understand the message, you realize it's a very interesting idea and, to me, the best part of the whole movie. It's as if the director Luc Besson had come up with that idea (explained on that scene) and only for that reason he sought to justify the making of a whole movie around it, adding inconsistent details.

Lucy

Of course I've seen many movies worse than this, but many better ones too. It's a kind of science fiction thriller about the human condition and the abuse of drugs. The central premise had already been addressed by Limitless in 2011 (I think that in that other movie, the details were worked a little better), which takes off a bit of originality from Lucy and there where it's original, it's somewhat excessive, imposed, forced, lacking of fluency in the script, consistency in the plot and plausibility in the construction of the argument. I think the box office success was mainly due to Johansson's fame and not the film as such. For me, it's a movie of 5/10 and I don't recommend seeing it or don't seeing it. I recommend seeing the scene of the conversation, but for the rest, it's an action movie that seeks to entertain and, if one decides to ignore the inconsistencies, at times it achieves that.