“Lucy,” a sci-fi action thriller arriving in the heat of mid-summer, is a high-velocity sprint to the finish line.

Title character Lucy, an American student living in Taiwan, is a normal young woman one day; a superwoman the next. The wild ride Lucy takes in an approximately 48-hour period is nothing she anticipated.

Scarlett Johansson stars in this new film from Luc Besson. Having previously helmed “La Femme Nikita,” “The Fifth Element” and “The Messenger: The Story of Joan of Arc,” the French writer-director has much experience depicting heroines.

Clocking in just short of 90 minutes, “Lucy” is Besson’s most frenetic tale of female empowerment. Lucy and the murderous Chinese drug dealers who pursue her stay in constant motion.

The film’s frantic tempo derives from Besson’s high-concept. After an accidental, massive injection of a super drug alters Lucy’s physiology, her brain begins a sudden escalation in intelligence. The movie plays with the common misconception that humans normally use only 10 percent of their brain’s potential, as Lucy’s mind rapidly soars to an unprecedented 100 percent usage.

But brilliance of a kind unknown in the history of mankind comes at a terrible price. Lucy knows she has just 24 hours to live. There’s much to do before the deadline, but Lucy’s mega-intelligence helps her accomplish amazing feats, especially in the world of electronic communications, from TVs to cellphones.

“Lucy” is a visual spectacle. As the story jumps from Taiwan to Berlin to Rome and Paris, Lucy periodically experiences hallucinogenic episodes induced by the drug that’s continuously transforming her. Besson puts her colorful, trippy experiences on the screen.

Lucy’s infinitely enhanced memory allows her to recall the age of early humans, even the beginning of the universe. These episodes are indebted to Stanley Kubrick’s “2001: A Space Odyssey,” film adaptations of H.G. Wells’ “The Time Machine” and, more recently, Terrence Malick’s time-tripping “The Tree of Life.” All the while, Besson keeps the tempo racing.

In a story where things happen so fast, Johansson doesn’t have time to do much more than run with her character. In the film’s first few minutes, she’s credibly alarmed after an unscrupulous boyfriend entraps her in a potentially deadly scenario.

Later, the actress narrows her focus, severely so, on the mission the altruistic Lucy sets for herself. There is some attempt at emotional resonance, but it’s fleeting and not so effective. But then there’s no time in Lucy’s 24-hour action marathon for long goodbyes anyway.

Johansson’s co-stars include the stately Morgan Freeman as an American scientist whose theories and research involving the brain are right up the newly enhanced Lucy’s unexplored alley. She calls upon him to help. In Paris, Freeman’s Dr. Samuel Norman and his French colleagues gather for an understandably awestruck encounter with the prodigy.

With Freeman representing good, South Korean actor Choi Min-sik supplies evil as the supremely arrogant Chinese drug lord Mr. Jang. The film’s highlights include scenes of the new and improved Lucy’s confrontations with Jang and his vicious gang. Another co-star, Amr Waked, playing Lucy’s ally, Capt. Pierre Del Rio, shares perhaps the summer’s greatest chase sequence with Johansson.

The awe that Besson aspires to in “Lucy,” including his florid pre-historic scenes, looks undercooked and capricious next to his film’s gripping action sequences. The urgency he achieves in the latter scenes, however, make “Lucy” a heck of a trip.