Justin Lin's sci-fi odyssey is lighter and funnier than previous installments, which is the best thing it has going for it.

Despite an expansive universe stretched across over a dozen feature films and numerous television series, the appeal of “Star Trek” is pretty straightforward: a motley group of colorful characters hurtle through mini-adventures in deep space, sustained as much by their chemistry as the variety of alien civilizations in their path. The first two films in the rebooted franchise attempted to raise the stakes with various cataclysmic events threatening its cast of fresh faces, but “Star Trek Beyond” goes back to the television roots. Spectacular as it looks, this is a $150 million blockbuster about nothing.

A lighter, funnier effort than the previous installments, “Star Trek Beyond” reflects a changing of the guard. With JJ Abrams passing the baton to Justin Lin, the latest entry plays like a CGI-heavy “Fast and the Furious” movie set in the future, with fancy gadgetry and fast-paced showdowns taking prominence over plot. Simon Pegg does double-duty, returning to the role of Scotty and co-writing the screenplay with Doug Jung. The result has Lin’s eye for outstanding set pieces and Pegg’s ear for injecting familiar genre tropes with wit. There’s an odd disconnect between the movie’s undercooked conflict and its epic scale, to the point where it barely exists as more than a series of flashy moments. But its trivial qualities come as something of a relief — this is a movie engineered to avoid overextending its allure, which differs greatly from so many of its summer movie peers that do exactly that.

The overall inconsequential nature of “Star Trek Beyond” stands in stark contrast to 2013’s sprawling “Star Trek Into Darkness,” in which rising Starfleet leader Captain Kirk (Chris Pine) at one point loses his job, and at another briefly loses his life. At the beginning of “Star Trek Beyond,” he’s faced with a more immediate issue: Boredom. Three years into a planned five-year mission to explore the cosmos, the Captain explains in his starlog intro that boldly going where no man has gone before can get awfully redundant sometimes.

Lin’s camera glides beautifully through the Starship Enterprise, capturing the various familiar members of the crew — Spock (Zachary Quinto), Uhura (Zoe Saldana), Dr. McCoy (Karl Urban), Sulu (John Cho), Scotty, and Chekhov (the late Anton Yelchin, sadly given little to do in a thankless role). They’re all still there, pressing buttons, sharing drinks, beaming about on unspecified missions. “What is it we’re trying to accomplish?” Kirk wonders, and the answer just dangles there.

But then just enough happens to generate the semblance of high stakes: A mysterious alien object stored in the ship’s hull generates the interest of the villainous Krall (Idris Elba, under layers of makeup that suggest Klingon by way of triceratops), a criminal leader of unknown origins who invades the ship and uses his mechanical space army to take down the starship. The ensuing crash sequence drags on for minutes on end, unfolding as a breathless series of daring maneuvers, flying bodies and flaming debris that, for a brief moment, suggest real peril for everyone involved.

Unfortunately, once the Enterprise stops moving, the movie grinds to a halt as well. Lin grounds the crew on a boring planet alongside a lame bad guy. Krall’s eerie ability to sap energy from his prisoners receives just one tossed-off scene, and the reasons behind his evil intentions receive only a pithy explanation in the final act. Much of the movie finds various members of the Starship roaming the planet trying to figure out ideas for escaping it. This kind of scenario often sustained single episodes of the original show, but struggles to congeal as a single 142 minute package.

Per usual, some interactions generate more sparks than others. At first alone in the woods, Scotty comes across fierce survivalist Jaylah (Sofia Boutella), a pale-faced warrior apparently inspired by Jennifer Laurence’s individualistic teen in “Winter’s Bone.” Jaylah’s not the most original ass-kicker around, but her ability to manipulate invisibility fields and bound about the woodsy terrain with ease provides the movie with a nice burst of attitude.

Paramount Pictures

The rest of the cast just toys around, making it clear just how much these movies are driven by personalities. Much has been made in news reports about the decision to turn Sulu gay, a revelation that fills approximately three seconds of screen time. That’s as it should. Even as the last two films emphasized Kirk’s challenges with his father’s legacy in the captain’s chair, the core “Star Trek” cast have very little in the way of backstories. They’re defined by their exchanges with each other: Forget about Spock’s complicated backstory as a member of the Vulcan race; the stone-faced character’s big challenge in “Star Trek Beyond” is his relationship troubles with Uhura, and when he winds up stranded on the planet alongside the surly Dr. McCoy, the doctor takes on new duties as a shrink.

When they’re done feuding and teasing each other, the movie turns back to its bare-bones plot. Eventually, the survivors gather at a ramshackle base to plot a means of overtaking the Starship from the bad guys, yielding another set piece — this one based around motorcycles and jump cables — before Kirk finds an excuse to blast “Sabotage” for a breezy sequence that plays like a 3D “Space Invaders.”

Toss in a few more vibrant alien species and geeky one-liners (“There’s no relative direction in space, you have only yourself”) and voilà: While “Star Trek Beyond” lacks a center, it compensates with an endless parade of distractions. When the movie moves along at a breezy clip, it’s partly because it feels so purposeless. The central threat revolves around the most explicit MacGuffin in recent memory (a box that contains some enigmatic thing of unknown destructive potential that many different people want to get their hands on), and yet that’s enough to let the strengths stand out, particularly the stunning effects work.

The massive space port Yorktown is a swirling helix of human activity, while the Enterprise itself speeds through hyperspace in shiny closeups that would have been unthinkable just a few years back. As a franchise that celebrates technological progress, it’s only appropriate that the “Star Trek” movies have become a shining example of just that.

Nevertheless, this playful, meandering saga ultimately arrives at a bland third act finale featuring the so-called “Climbing Killer Syndrome” in which the antagonist must irrationally flee to an inescapable high elevation while explaining his entire motive. Toss in a tenuous connection to some earlier “Star Trek” entries to keep the series’ street cred in check and everybody gets to go home happy.

Nothing about this polished movie suggests the slightest attempt to reinvent the wheel. If “Star Trek Beyond” existed outside the arena of reboots and sequels that mandated its existence, the movie’s casual air might be downright radical for such an extensive production. Instead, it’s just a sturdy riff on the same old routine.

Grade: B-

“Star Trek Beyond” opens nationwide on July 21.

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