LOS ANGELES (Variety.com) – It begins with the accent. Kate Winslet hasn’t significantly disguised herself in order to play a cop in small-town Pennsylvania in HBO’s “Mare of Easttown,” until in the first two minutes of the first episode when she informs us that she investigates the burglaries, and the ooooo-verdoses — that first “o” as broad as a football field — “and all the really bad crap that goes on around here.” Shortly thereafter, a scene in which she buys a tank for a new pet turtle seems constructed at once to show her frugality, her concern for her grandson, and the way that Winslet has taught herself to refer to the liquid this reptile will need as “wooder.”

The Philadelphia intonation Winslet has learned — and mastered, much as she has Mid-Atlantic (“Titanic”) and Polish (“Steve Jobs”) before — leaps out, and not merely because we don’t hear it too frequently on screen. It’s the clearest way to differentiate Mare Sheehan from the rest of Winslet’s body of work. This actor has had a tendency, in her best work, to use physical stillness and deep thought to reveal, an inch underneath, fractious internal chaos. “Mare of Easttown” capitalizes on this skill. At its best, the series gives Winslet space to deliver a performance that resists fireworks in favor of flickering doubts, insecurities, and concerns. Winslet’s accent gets your attention first, but soon, you’ll be most closely watching her when she’s doing a million things silently.

And viewers will be thankful for Winslet’s steadiness at the center of a series that spends a fair amount of time circling its story before deciding what it is. Mare Sheehan is a former high school basketball star who followed her father into police work; she lives with her mother (a typically strong Jean Smart), teen daughter Siobhan (Angourie Rice), and grandson (Izzy King) in a house whose busy noisiness conceals silences, things rarely discussed — like the absence of Mare’s late son, or the circumstances around her divorce. Mare is rarely without a beer in her hand but doesn’t often seem truly drunk — just anesthetized against the pain that comes with wanting more. Like her childhood friends and teammates, she couldn’t and still can’t imagine herself out of the vortex of the town in which she grew up. That town is now defined by opioids, the crime that follows in their wake, and certain overriding hopelessness; no wonder the memories of Mare’s basketball career are such a big deal. The arrival of a novelist new to Easttown (Guy Pearce, in a reunion with his “Mildred Pierce” costar) presents Mare both with an alluring romantic prospect and the nagging sense that she’s somehow being mocked by this erudite man or perhaps just by a universe that’s treated her with something less than loving kindness.

She may not be a conversationalist on par with Pearce’s erudite writer — indeed, one of the more moving moments comes as she struggles to express what she hopes to get out of therapy with a new provider — but Mare has a fundamental inquisitiveness that speaks to an active mind. Early in the series, she’s all but outright given up on a missing-persons case concerning the daughter of an old friend (Enid Graham); a perhaps unrelated homicide awakens her curiosity. This focused intensity comes in a mercurial package, governed by impulse and mood: Her relationship with a county detective brought in to cooperate with or supervise her (Evan Peters) stutters at first as he learns the ways she works. Though he’s superior, she sets the climate.

Mare’s relationship with Peters’ Detective Colin Zabel — a character whose sharp mind and generosity make for a flattering association with similarly-named series director Craig Zobel — is a bright spot in a series governed elsewhere by vexed or painful relationships. Mare and her oldest friend (Julianne Nicholson) have a shared language of frustration and pain; she and her daughter just talk past one another; with her mother, Mare is perpetually annoyed, but for occasional, strange moments when the soundtrack goes zippy and the series seems to strain for a sort of zany all-under-one-roof family comedy. And what she recalls of her time with her son just makes her hurt. With Zabel, she has someone who wants to listen, and — crucially — to hear Mare’s insights, not just her hard-luck story.

Peters’ chemistry with Winslet, a formidable scene partner, is an achievement. It also is a relief. There’s a certain small-town pessimism throughout this series that Peters’ presence eases. Zabel conjures a mood of anguish that can feel a bit like a black hole — at times, not enough light, or insight, is allowed to escape the sorrow of Mare and the community she serves because she couldn’t break free. And screenwriter Brad Ingelsby — most recently the writer of the addiction drama “The Way Back” — can spend time wallowing in characters’ pain rather than using it to reveal. A documentary project young Siobhan is working on is a jerry-rigged excuse to trigger Mare into a deep well of sadness — and she hardly needs an excuse anyhow. And some lines of dialog seem written with the intent to conjure glum desperation but end up just feeling, well, written. (Consider when Mare offhandedly asks a priest “When you’re up at the altar, preaching to the congregation, do you ever get the feeling no one’s listening?” The double meaning — is she referring to the congregants, or to God? — feels intentional, and too worked-over by half.)

But Winslet holds one’s gaze. Just as she did in the knotty HBO “Mildred Pierce” 10 years ago, she makes art out of a quiet watchfulness that’s anything but placid. Unlike in that project, she often pushes against, rather than working with, the direction and script. The show seems at times most interested in Mare’s misery. But Mare wants, especially, to be seen for who she is, and Winslet helps her get there. “Doing something great is overrated,” she tells Zabel in a moment of real candor deep in the series, “because then people expect that from you all the time. What they don’t realize is you’re just as screwed up as they are.” We see, at some length, the ways in which Mare is screwed up. But the achievement of Winslet’s performance is that for as much as Mare may seem like a victim, we come to believe she has it in her, perhaps more than ever before in her life, to be great.

“Mare of Easttown” premieres Sunday, April 18 at 10 p.m. ET/PT on HBO.