One of Hollywood’s hottest action stars will inject a shot of adrenaline into the moribund summer box office this weekend, when revenge thriller “Lucy,” starring Scarlett Johansson, hits screens.

Distributed by Universal, “Lucy” will unroll across 3,172 theaters this weekend and should shoot up an estimated $36 million. That would be a nice return on a $40 million budget and a sign that audiences don’t always need their onscreen mayhem to arrive pre-branded, pre-merchandised and plucked from venerable comicbooks or toylines. It’s the rare original film that looks ready to upend the steady stream of same-olds.

Sadly, “Lucy’s” main competition, “Hercules,” is looking less than godly. Paramount and MGM’s $100 million reimagining of the old Hydra killer is on track to debut to roughly $25 million across 3,600 locations, which would be a scrawny showing given the high cost of the production.

Brett Ratner (“Tower Heist”) directed the film, with Dwayne Johnson playing the strongest man on earth. He’s the main selling point, and the likable star can be counted on to turn out his base of fans, but the picture has had difficulty differentiating itself from the glut of sequels and special effects extravaganzas. Though it is rated PG-13, it may still lose teenage ticket-buyers to the R-rated “Lucy.”

“They’re both gunning for the same key demos, and ‘Lucy’ seems to be the stronger of the two,” said Phil Contrino, vice president and chief analyst at BoxOffice.com.

With the summer box office down 20% from last year, the studios are hoping to reverse the negative momentum and provide enough compelling product to lure people back into the multiplexes.

“Lucy” centers on a woman who unlocks superhuman abilities after being injected with drugs that allow her to access more than the standard 10% of the brain — it’s another 90% that Hollywood, though not science, contends is devoted to general kick-assery.

Directed by Luc Besson (“The Professional”), the production has been bolstered by gritty promos and has benefited from Johansson’s gun-toting role in “Captain America: The Winter Soldier,” the top-grossing film of the year in the U.S. If the film works, she could emerge as the successor to Angelina Jolie as the preeminent female action star.

Also hitting theaters this weekend is Rob Reiner’s romantic comedy “And So It Goes.” Targeting older adults, the counterprogrammer stars Michael Douglas and Diane Keaton and is being produced by Clarius Entertainment. It will roll out at 1,800 theaters and should do $8 million to $10 million.

In limited release, Woody Allen will debut his latest confection, “Magic in the Moonlight,” in 17 theaters in New York, Los Angeles, San Francisco, Chicago and Washington, D.C. Summer has been good to the nebbish auteur, with “Blue Jasmine” and “Midnight in Paris” making $34.4 million and $56.8 million, respectively. A middling critical reception might make hitting similar numbers more difficult this time, but Allen has his devotees, and the picture should do well in Europe. Sony Pictures Classics is distributing the film, having handled the director’s recent hits.

Also of note: “A Most Wanted Man,” the espionage thriller that marks one of Philip Seymour Hoffman’s final roles, bows in limited release. Hoffman died of a drug overdose last February. He plays a German intelligence officer in the well-reviewed adaptation of John Le Carre’s novel, which Roadside Attractions will unveil in 350 theaters.

In holdover territory, expect last weekend’s champ, “Dawn of the Planet of the Apes,” to drop into the $20 million range and fight for second or third place with “Hercules.” Universal’s micro-budget horror film “The Purge: Anarchy” will have a steeper fall from its $29.8 million debut and should scare up around $10 million.

Overseas, “Hercules” will try to capitalize on Johnson’s global star power, as it opens in 19 international markets this weekend, including Russia, the United Kingdom and Australia. “Lucy” will begin its foreign rolling out next week in Australia, New Zealand, Bulgaria and Panama.

Between “Lucy” and next weekend’s “Guardians of the Galaxy,” maybe the movie business will be able to unlock the other 90% of the audience that hasn’t been showing up.