Although the premise, that humans only use 10% of their brain (we use 100% of our brains), this is an extremely entertaining movie, along the lines of LIMITLESS. Lucy (Scarlett Johansson) is a not-so-bright woman who is coerced into becoming a drug mule, only the drugs she is carrying leak into her system and begin changing her, so that she eventually transforms into something that is no longer human. Although there's really no real science behind this premise, Morgan Freeman as Professor Norman almost makes you believe it's true.
LUCY is more enjoyable than TRANSCENDENCE but the latter is far better written.