After her mesmerizingly out-there performances as an artificially intelligent being in “Her” and a come-hither extraterrestrial in “Under the Skin,” Scarlett Johansson takes a logical next step into the title role of “Lucy,” an agreeably goofy, high-concept speculative thriller about the first human being to successfully harness 100% of her brainpower. In no other sense, however, does the word “logical” apply to writer-director Luc Besson’s return to blockbuster form — which is to say, his latest aggressively stylish, self-consciously feminist, gratuitously globe-trotting pulp-trash extravaganza. Giddily recycling everything from “2001: A Space Odyssey” and “The Matrix” to yakuza actioners and National Geographic documentaries, it’s a garish, trippy, wildly uneven and finally quite disarming piece of work, graced by a moment-to-moment unpredictability that will pique audience curiosity but may put off those who prefer their summer movies on the more conventional side.

Although it represents a significant roll of the dice as the most expensive project ever undertaken by the filmmaker’s EuropaCorp shingle, “Lucy” should capitalize on its strong international elements and Johansson’s bankability to become Besson’s biggest worldwide hit as a director since “The Fifth Element,” no small feat for an f/x-heavy original property in this over-franchised day and age. And unlike that bloated 1997 dystopian juggernaut, the film manages to clock in at a surprisingly sleek and multiplex-friendly 88 minutes, and its abrupt but elegant conclusion has the curious benefit of making this extravagantly silly entertainment seem somehow smarter and more enigmatic in retrospect than it does while it’s unfolding.

(The well-documented fact that humans actually do use most of their brains manages to debunk the movie’s premise without in any way detracting from its loopy pleasures.)

The first half of Lucy contains the most energetic and purely entertaining filmmaking Besson has produced since The Fifth Element, packed with pulpy action, pseudoscience, title cards, sped-up montages, and teasing associative cuts.

Instead, this is closer to an art house film than a mainstream offering and the hue and cry from those expecting the summer's next big blockbuster will be loud indeed. Sure, there's plenty of action in Lucy but it's not of the rah-rah sort. This is a more contemplative sort of motion picture. The climax in particular, although as visually impressive as it is bizarre (Tree of Life, anyone?), is more likely to frustrate than satisfy.