Maura Tierney as Helen and Dominic West as Noah in “The Affair.” (Paul Sarkis/Showtime)
TV critic

After three seasons, it felt as if we’d arrived at a natural end for “The Affair,” Showtime’s absorbing psychological drama about relationships and conflicting viewpoints.

When last we saw Noah Solloway (Dominic West), his marriage to Alison (Ruth Wilson) was kaput, he’d served a prison term for a vehicular manslaughter he didn’t commit, and he was getting over a painkiller addiction so intense it turned him dangerously paranoid.

After so much runaround, Noah was seen standing outside the brownstone of his first wife, Helen (Maura Tierney), peering in on her good luck: She got custody of their kids and fell in love with Vic (Omar Metwally), the family’s handsome pediatric surgeon. It seemed appropriate to leave Noah outside that circle of happiness; even in those scenes told from his point of view, Noah always tended to be an entitled jerk, an impulsive cad prone to mansplaining. Acutely aware of his own suffering, he’d probably turn that pain into his next novel.

But wait (as they say), there’s more: Season 4 turns out to be an unexpected treat. The new episodes capably reignite the show’s original allure, discarding some unnecessary bloat and focusing once more on “The Affair’s” basic premise, which is that no two people will ever view the same occurrences and facts the same way. The show is also very good on the subject of long and unintended consequences, the sort of mistakes that reroute entire lives.

That’s not a particularly profound revelation to anyone who’s ever been in a relationship (or had an affair), but it remains a fascinating narrative device where “The Affair” is concerned. In Sunday’s premiere, we’ve skipped ahead a decent amount of time. Helen and Vic are married and living in a gorgeous hillside home in Los Angeles, with Helen’s two younger children. (The older two have been shipped off to wherever cable’s used-up trouble teens go.)

Noah has also moved to L.A., in an attempt to remain close to his kids, and, in a very Noah-like display of privilege, he teaches English at a charter school in Compton, where he pontificates on Orwell’s “Animal Farm” to a room full of stereotypically disengaged minority students. Noah, of course, thinks he’s their literary savior — particularly one boy, Anton (Christopher Meyer), whose aloof underachievement masks his potential brilliance.

Back on Long Island, meanwhile, there’s Alison, whose affair with Noah launched a hundred doomed ships. She now works as a counselor and raises her daughter, Joanie. A group of eager investors are about to buy the franchise rights to the successful lobster-roll restaurant she owns with her ex-husband, Cole (Joshua Jackson, who could carry the whole show, if necessary). In his world, Cole tries to placate his restless wife, Luisa (Catalina Sandino Moreno), who has realized in the Trump era that her chances for full citizenship are slim to none.

While reacquainting ourselves with these characters, there’s a familiar and almost inexorable pull into their lives. Alison meets a potential new love, a Marine veteran named Ben (Ramon Rodriguez), who, from her perspective, is charming and honest; Cole’s take on the man differs significantly. And in Tierney’s consistently superb portrayal of Helen, we see how her take on the same argument with Noah still varies wildly from his. What’s most clear now is that all these people are forever enmeshed in one another’s business — even the relatively innocent, like Vic and Luisa, are caught up in it.

Along with the emotional messiness, “The Affair” feels duty bound to include some bit of drama or fresh menace with each season. Through carefully constructed moments of flashing forward and back, viewers will figure out that Allison has gone missing, and Noah has returned to Montauk to help Cole look for her.

There’s quite a bit of subplot occurring between here and there — a task “The Affair’s” creators (Sarah Treem and Hagai Levi) and writers handle with surgical precision. But it leaves one wondering if the producers (or the network) might ever trust “The Affair” to exist purely on its smaller and more intimate moments, without needing a crime or a mystery to solve along the way. “The Affair’s” shenanigans are never as good as its simpler sins.

The Affair (one hour) returns Sunday at 9 p.m. on Showtime.