After you've seen Lucy, come back and listen to Slate's Dana Stevens and Forrest Wickman discuss the film, starring Scarlett Johansson, by clicking on the player below. They are joined by Sam McDougle, who wrote on the film's faulty science.

The first living thing we see in Luc Besson’s Lucy (not counting a close-up of primordial dividing cells) is the original Lucy, the female Australopithecus afarensis whose skeleton constitutes one of the oldest and most complete specimens of humanity’s first ancestors. She’s drinking by a brook in a fern-covered primeval forest—and then suddenly we’re in modern-day Taipei, watching the 21^st-century version of Lucy (Scarlett Johansson) argue with her skanky boyfriend. (He wants her to carry a briefcase whose contents he won’t disclose into a meeting with a Korean gangster, which to me is always a relationship red flag.)

Get used to that kind of geological era-skipping if you go see Lucy—an entertainment choice I wouldn’t recommend, but one you might not regret if you dial your expectations down (or your drug intake up). This trippy transhumanist sci-fi fantasy—emphasis on fantasy, as in “none of this could ever possibly happen and my disbelief was at no point remotely suspended”— features a neurally augmented heroine who acquires the ability to transport herself across space-time. At any given moment, she might take us to a Taipei nightclub or a Paris hotel room, back in time to the age of the dinosaurs or forward to the final moments of Earth’s existence. The only place she never took me was to a place of caring what happened next, whether to Lucy I, Lucy II, or the planet.

How did modern-day, non-Australopithecus Lucy get herself into a situation where she was forced to carry a briefcase of mysterious contraband for her boyfriend of one week? Besson, who also wrote the screenplay, has no interest in showing us where our heroine comes from or what she was doing in Taiwan. Except for one intimate phone call that I’ll discuss further on, the film offers almost no glimpses into the protagonist’s inner life. All we know is that, shortly after being taken prisoner by the Korean crime boss (Oldboy’s Choi Min-sik), Lucy wakes up with a surgical incision in her abdomen. She’s been implanted with a sealed pouch containing a superpowerful new neural-enhancement drug and must now serve as a mule to transport the substance back to the U.S.

But before Lucy can board a plane home, a kick in the stomach from one of her brutish jailers breaks open the pouch, dispersing the drug into her system. With an ominous chord from Eric Serra’s electronic score, a figure appears, filling the screen: 1 percent. (Apparently the pre-augmentation Lucy was no Rhodes scholar.) As the movie progresses, so will this young woman’s use of her cranial capacity, accompanied by periodic full-screen updates. By the time Lucy reaches 20 percent, she’s already learning Chinese from a few street signs and casually vaulting into the air to hang from the ceiling. (I hadn’t realized it was the inadequacy of human cognition that was keeping my feet on the ground, but there’s a lot you miss when you’re operating in single-digit percentages.)

Never mind that the pop-science truism about humans using less than 10 percent of their brains (repeated here by Morgan Freeman as a neuroscience professor teaching Exposition 101) is sheer flapdoodle. The idea of an individual human exponentially expanding his or her mental and physical capacities could still make for a potentially thrilling sci-fi premise, albeit not an unfamiliar one; in the last few years, both Limitless and Transcendence have imagined the ascent of a tech- or drug-enabled Übermensch. But Johansson’s affectless, pneumatic Überfrau is the least interesting version imaginable of the archetype.

For one thing, there’s the no-inner-life problem I mentioned. From the moment she gets chemically ensmartened, Lucy loses virtually every shred of doubt, pain, fear, or physical vulnerability, making her a singularly unrewarding heroine to continue investing our own emotional resources in. If she can effortlessly extract herself from any dangerous situation and reduce all her enemies to helpless, flailing clowns, why keep piling on the action scenes to prove it?

There’s one strange, rather lovely moment on the phone with her mother when Lucy reverts to a state of oceanic bliss. (She’s being operated on, anesthesia-free, by a surgeon whose last patient she just shot and pushed off the table, but that’s not important right now.) She describes sense memories from her earliest infancy in detail (“I can taste your milk in my mouth”) before signing off with a tearful declaration of love. This appears to be the rapidly evolving Lucy’s official farewell to emotion, since for the remainder of the film, she registers little to no regard for human life, let alone the finer shades of family feeling.

Lucy may be intellectually and physically hyperadvanced (eventually, she reaches the point of being able to scroll through different realities like someone swiping a computer screen), but she’s a tactical and moral numbskull. Again and again, she makes choices that result in the maximum possible civilian body count. When a sympathetic Parisian cop (Amr Waked) offers to pick up the phone and call off the gendarmes hot on their trail, Lucy refuses and speeds the wrong way around the Arc de Triomphe, leaving multiple car crashes in her wake. Entering a room full of potential baddies, she makes no effort to distinguish between the innocent and the guilty, just polishes off the lot.

You could imagine a fascinating version of this film with Lucy as a troubled antihero, someone struggling with the implications of her new powers. Instead, for most of the film, she’s a powerful, selfish automaton, motivated principally by the need to locate and secure an ongoing supply of the drug she needs to stay superstrong. (Called CPH-4, it comes in the form of bright-blue crystals whose effects when snorted make Walt and Jesse’s product in Breaking Bad look like Pop Rocks.)

Scarlett Johansson as sublime portal to the posthuman future: That seems to be a thing lately, whether she’s playing a fast-evolving digital intelligence in Her, a deadly space alien disguised as a human being in Under the Skin, or whatever combination of Neo and the Terminator she’s supposed to embody here. It’s easy to see why one would cast Johansson in such a role. Her combination of earthy sensuality with cool, cerebral remove—not to mention the best husky female voice since Kathleen Turner—makes it entirely plausible that Johansson might, in fact, have been designed by alien overlords to lure men to their deaths in featureless black rooms, as her character does in the bone-chilling Under the Skin. But Besson’s Lucy, for all its whoa-dude-my-mind-is-blown aspirations, is too dumb to engage either Johansson’s intelligence or the viewer’s.

There’s some camp fun to be had in Lucy’s hallucinogenic last scenes, when, finally approaching 100 percent capacity, Lucy mentally whooshes off for a trip around the world and backward in time, eventually engaging in an E.T.-style finger touch with her curious prehistoric namesake. I’m glad both Lucys were able to find meaning in the encounter Besson’s film had been elaborately setting up for them since the first frames. If only I had the cerebral capacity to understand what that meaning was, or the cardiac capacity to care.