In "The First Purge," the genesis of an annual twelve-hour period where all crime, including murder, is rendered legal in the U.S. is predictably—and all too plausibly—paved with carnage, betrayal, and governmental corruption. Directed by Gerard McMurray, this prequel to the smash-hit franchise should please undiscerning fans while giving others a sustained whiff of déjà vu. While its sociopolitical parallels to the real world are frighteningly warranted and still the most effectively pointed aspect of these films, the screenplay by James DeMonaco (who previously directed 2013's "The Purge," 2014's "The Purge: Anarchy," and 2016's "The Purge: Election Year") is of a noticeably staler ilk. Characterizations are more pedestrian, the trajectory of the plot is by now overly familiar, and there are few fresh avenues to travel down. In light of the country's current divisiveness harkening from the vile, morally bankrupt commander in chief, the series has progressively edged away from escapism and closer to that of a depressing harbinger.

Unemployment is rising. The opioid epidemic is at an all-time high. And in Washington, D.C., a radical new political party called the New Founding Fathers of America has ascended to power, its twisted, distinctly un-American beliefs festering in the minds of its followers. As a hoped-for means of cutting down on crime by making it legal during one night of the year, a psychological experiment called The Purge is about to take place on Staten Island. Citizens who agree to stay put in the New York borough are promised five-thousand bucks apiece—and significantly more if they agree to take part in the permitted homicidal crime spree.

That an area full of low-income housing projects has been chosen is not a mistake, and anti-Purge protester Nya (Lex Scott Davis) knows it. Her biggest priority is keeping her teenage brother Isaiah (Joivan Wade) safe, but she is unaware he has bypassed the ferry meant to transport him out of the endangered zone and instead set his vengeful sights on unhinged neighborhood adversary Skeletor (Rotimi Paul). Meanwhile, Nya's ex, community drug king Dmitri (Y'Lan Noel), tosses away his nonviolent plans for the evening when he is targeted for murder by Capital A (Christian Robinson), an underling hoping to usurp his reign. Surveilling the experiment is Dr. Updale (Marisa Tomei), a by-the-book behavioral scientist who has spearheaded the Purge movement, and crooked Chief of Staff Arlo Sabian (Patch Darragh), about to put a horrific wrench in her data by genocidally skewing the results.

"The First Purge" works best as a gnarled, grotesque cautionary fable, unafraid to shy away from incendiary imagery. More than ever before within the series, there is an undeniable race-related component at work, one that is too on-the-nose to be considered metaphor (truckloads of hooded Ku Klux Klan members prowl the streets in search of prey, while a squad of police officers are briefly seen hunting down an unarmed black man). It is more than a little ballsy for director Gerard McMurray to dare go to these uncomfortable places, though his failure to provide any kind of insight renders them exploitative. To be sure, there are astute touches within the story as a whole (once The Purge begins, signaled by portentous air raids heard across the burg, the control-room staff is perplexed to find a raging block party rather than raging killers on the loose). One scene where Isaiah is stalked by purgers keeping watch over him from surrounding windows, their glowing contact-lens trackers transforming them into demonic Halloween decorations, is genuinely creepy, but there simply aren't enough moments of macabre inspiration like this one.

The cast is functional, the actors' roles too thinly developed to break free from archetypes. Of the leads, Lex Scott Davis (2018's "Superfly") is most sympathetic as Nya, a young woman trying to take care of brother Isaiah while struggling to break free from her impoverished circumstances. As the increasingly concerned Dr. Updale, Marisa Tomei (2017's "Spider-Man: Homecoming") is sorely underused; while Tomei is primed and ready to dig beneath the surface of a woman realizing she has made a grave mistake, the script consistently lets her down until she is unceremoniously tossed aside. Perhaps the scene-stealer of the ensemble is Mugga (2009's "Precious: Based on the Novel 'Push' by Sapphire"), a ray of lively comic relief as Nya's fiercely protective but intensely frightened neighbor Dolores. The appearance of Melonie Diaz (2013's "Fruitvale Station"), a standout in just about everything, might be the picture's biggest head-scratcher; she shows up early on for about a minute as a prospective purgegoer and is never seen again.

"I'm worried about our future," young teenager Selina (Kristen Solis) confides in Nya as they attempt to barricade themselves in an apartment under siege. Her words hold a certain power precisely because they are so prescient to our own current concerning political climate. "The First Purge" knows exactly what it's doing with these loaded correlations, even as the derivative picture supporting them too frequently runs on fumes. Wading through a narrative of familiar beats before devolving into a climactic shoot-out, the film lacks the dread-inducing verve and personality of its three predecessors. As a whole, "The First Purge" is not without merit—even when it's less than eloquent in its delivery, at least it has something on its mind—but this is the first installment where signs of series fatigue are in evidence. By the end, this viewer's overwhelming reaction was, "Is that all there is?"