The promotional material accompanying HBO’s “The Deuce” is better at explaining what the show is about than the show itself is.

Anyone who stayed with “The Deuce’s” strong (yet not wildly raved-about) first season could tell it’s obviously about prostitution, pornography, mob influence and other criminal doings in and around Times Square in the early 1970s. The grit and grotesquerie make a fine, if lurid, period piece that is rich in characters — particularly Maggie Gyllenhaal’s sublime portrayal of Candy, an older prostitute who becomes a “triple threat” porn actor, producer and director, yet is nevertheless mistreated by the men around her.

Still, viewers are left wondering about the show’s overall reach and theme. Is it a protohistory of exploitation? Is it a longer piece about the cleanup of Times Square (and thereby the loss of a far more interesting New York)? Is it a subtextually feminist take on the rights of sex workers?

This season, “The Deuce” is making itself more clear: The show, to quote HBO directly, is “chronicling the rise of pornography and the multibillion-dollar industry’s transformation of American culture.”

Good to know — even if Season 2 (currently airing Sunday nights) still exhibits a conflict between the general and the specific. I’m not entirely convinced “The Deuce” needs to burden itself with grand statements about our sexed-up culture and how we got here; simply on the merits of its frank, thoughtful storytelling and acting, it’s a perfectly fine riff on the wages of sin back in the day.

That day is now late 1977 and early ’78 (roughly a six-year jump forward), in which the goon profiteers of Times Square have benefited mightily from the loosening of indecency laws and the triumph of Me-Decade morals. The peep-show booths are more sophisticated; theatrical porn films are released at a steady clip (with the industry giving itself annual awards); and those discreet houses of ill-repute built with mob money have become slick operations.

James Franco returns in the dual role of the twin Martino brothers: Vincent, the responsible one with something of a conscience, is still operating bars — including a hopping after-hours discothèque — along with managing a thriving peep-show arcade and a couple of brothels. The good-for-nothing Frankie has his paws in every cookie jar, stealing profits and pressing his luck. Even with different haircuts (some viewers struggled to tell Franco’s characters apart last season), it’s hard to make a case that either character brings much to the show.

Meanwhile, the city’s effort to fumigate Midtown Manhattan and make it safe for tourists (and redevelopment) pushes its way into “The Deuce’s” narrative. “The fact that we’ve got wiseguys torching up each other’s whorehouses — that needs some attention,” a police commander observes, and certainly it’s a path to the sort of bullet-to-the-head violence and systemic corruption that viewers associate with Simon, Pelecanos and company. It’s male detectives, male mob heavies, male pimps and even a couple of men trying to open a bigger, fancier gay bar in the Village. Yet “The Deuce” is always more interesting when it shifts to the perspective of its female characters, especially as they begin to realize their roles in this revolution.

Dissatisfied with porn’s limited cliches (plumbers and pizza boys having sex with hapless bimbos), Candy tries to come up with a sophisticated and complex take on fairy tales — movies that will address the deep psychological signposts on the path to pleasure.

Her producer, Harvey (David Krumholtz, who is just a seedy delight in this part), is both sympathetic and skeptical: “I get what you’re going for, I’ve read my fair share of Bettelheim,” he says. “I am familiar with the Freudian s---. Sex and death and, you know, annihilation of innocence and matricide and infanticide, et cetera. . . . But if the [sex] is not good, then I’m not buyin’ it. Not by the hair of my chinny-chin-chin.”

“What’s a ‘Bettelheim?’ ” Candy asks someone afterward, but her aim is true, even as she must endure the kind of mistreatment that could set the Me Too movement’s hair on fire. Her steadfast independence inspires her actresses, who have become less dependent on their pimps and the street, including rising star Lori (Emily Meade) and the increasingly assertive Darlene (Dominique Fishback). They’re the ones, after all, who know the most about selling fantasy. And it’s Vincent’s girlfriend Abby (Margarita Levieva) who gets hip to a movement to help prostitutes find better lives and break free of abusive pimps.

Yet “The Deuce” and its makers (and its network) just can’t shed that affinity for macho conflict. And, to their point, no chronicle of the rise of porn would be complete without a frank depiction of male dominance. But if “The Deuce” really wanted to nail down its mission and gain more traction with today’s fickle, fleeting audiences, the press release would proudly and unequivocally say: This is a show about women and the rise of porn.

The Deuce (one hour) airs Sundays at 9 p.m. on HBO.