The premise is reminiscent of The Hand that Rocks the Cradle, a film about an evil nanny causing death and destruction in her path. The stakes in Lucy, though, are very low and as a psychological thriller, it is hugely disappointing. Plot points don't always make sense, and there are few clues as to why Ashling does what she does. Is it class warfare? Maybe psychological manipulation or something darker? The audience the night I saw it was primed to scream, but the revelations are laughably banal and the suspense and danger do not accumulate. We are told several times, for instance, that Lucy is at odds with Ashling, but we don't see it. They seem to get along just fine as they dance, play, and eat soup together. Even the ending, which promises a tense standoff between the two adults, is both too timid and too tepid. When the final lights went down, there was a noticeable sense of dejection in the applause.