Lucy is a kinetic frolic of a movie. It's part true-blue science fiction and part action movie and all blended up in a mash-up that is compelling at first but then loses its path a bit towards the end. First a small summary.
Lucy (Scarlett Johansson) is a student in Taiwan who is tricked by her boyfriend into becoming a mule for a vicious drug lord (Choi Min-sik). She accidentally ingests her cargo when she is abused by her captors and the synthetic drug elevates her evolutionary state allowing her to access an every increasing percentage of her brain power. She goes from victim to avenger as she is able to use her mind to move objects, read minds, see through time, and access nearly any tech she sets upon. She goes from a scared young woman to a calm killing machine with no apparent affinity for her fellow human beings. Her mission to acquire more of the drug brings her to Europe and a scientist (the ubiquitous Morgan Freeman) who might have a small inkling of what is happening to her. She involves a French policeman (Amir Waked) to assist her and to state off the drug lord who wants revenge and his drugs. Much death and mayhem ensues.
As played by Scarlett Johansson the character of Lucy begins as a terrified young woman who the audience has some real care for, but for this viewer at least her transformation into superwoman causes her to become something completely other and whatever empathy we have for the character disappears as she whips across the globe leaving a wake of death and destruction in her path.
The director Luc Besson delivers a visual feast but sadly the story loses its way when the heroine becomes effectively inhuman. We know she can do anything so what she does makes little difference in the end. It's splendid at times to watch, but the emotional connection withers throughout the film.
I was reminded to some extent of the stories of Olaf Stapledon, yarns that begin with characters can relate to but who expand their consciousness to bewildering extremes and in some ways become merely thought experiments in more ways than one. Lucy is a flick that's fun to watch but its heft is less than it seems and its connection to the viewer diminishes to the point of uncaring.
I recommend you see this one once, but I doubt you'll feel the need to see it again.