Lucy (Scarlett Johansson) is a party girl wasting her days in Taiwan. She gets roped into a drug mule operation for the Korean mob, which ends up with the dope exploding inside of her. But rather than having a terrible, Maria Full of Grace-style tragic death-from-overdose, Lucy gets supercharged with the stuff: a synthetic compound that unlocks your brain capacity and gives you crazy superpowers! Meanwhile, neuroscientist Professor Norman (Morgan Freeman, because of course) explains everything that's happening to Lucy in the context of a lecture about how, if humans could access 20% of their brain capacity (like dolphins!) then they could become capable of so much more.
It's Luc Besson time, everybody! That means check your brains at the door and buy an extra-large popcorn, because critical thought and logic are for nerds! It's all good, though, because when Besson's behind the camera, it's always good times. His tone ranges from mournful (The Professional) to kookoo bananas (The Fifth Element). Lucy is more on the latter side of the spectrum, although you do get to watch Johansson sport her Serious Face for the film's brisk 90-minute run time. This is fitting, because the film needs to take itself just this much seriously in order for it not to fall apart like the doofy Lego set it is. You believe that Lucy--once she ditches the miniskirt and low-cut top for more a more murder-friendly ensemble--understands that she is on her way to becoming a supreme being, so joining her on the ride is all the more enjoyable.
What powers does she have? Think of it like Batman's utility belt: Lucy can do whatever she needs to do depending on what the situation immediately calls for. She is alternately Neo from The Matrix, Obi-Wan Kenobi and Chev Chelios from Crank. She's always 100% extremely dangerous, even when her brain is only at 40%. The catch is that her cells multiply at too fast of a rate for her to survive long, so it's sort of like she has the limitations of Super Mario Bros.'s Starman with the capabilities of Doom's God Mode, with No Clipping turned on for good measure.
The blood runs plentifully and often in Lucy, straight from the brain to the rest of the body, which needs it much more for this sort of affair. 90 minutes is all a film like this merits: when it starts dipping into 2001/Tree of Life territory at the end, you can tell Besson's just spinning his wheels. Not that it's not totally entertaining to watch him do so. It's fun to stare at the sun, too, but you don't want to do it for long.