The series’ drumbeat is a toxic father-son relationship. Liev Schreiber plays Ray Donovan as a scruffy, taciturn presence who is up against an equally unrelenting force in his ex-con father, Mickey, played by Jon Voight, a paralyzing, unpredictable, but oddly lovable character audiences can’t help but root for, which says something about the writing, casting, and performances.

Picking up where the seventh season’s cliffhanger ended, Mickey is on the run, and Ray is determined to find him before everyone else does, while his brothers Terry (Eddie Marsan), Bunchy (Dash Mihok), and Daryll (Pooch Hall) juggle the usual existential inquiries and a past from which they never seem able to run. Through a series of flashback sequences (there are several of them in the movie) with Christopher Gray as the young Ray and Bill Heck having tons of fun as Mickey, Ray’s childhood is continually fleshed out, and the movie answers dangling questions about this long-running story of tumultuous familial drama. “You always were a piece of shit,” a young Ray confronts his drunken father, and they throw punches at each other. That pretty much sums up their volatile relationship, and yet, now as grown men, one just can’t seem to exist without the other. It’s titled “Ray Donovan,” but it may as well be called “Ray & Mickey,” because Voight’s performance is every bit as responsible for the series’ thump. He is a “piece of shit” father; Mickey knows this and has accepted it. Yet the character is painted in a way that engenders empathy. There’s a streak in Mickey that suggests he cares for his children. It would be easy to hate him, but his love of life is palpable. He understands the shitty hand that he’s been dealt, and he plays the hell out of it. The audience roots for him and wants him to win. Maybe he reflects a failure in all of us; a flaw we acknowledge but are powerless to do anything about. It’s not a coincidence that alcohol abuse is itself a character in the series. Mickey drinks; Ray drinks; his brothers drink, burying their pain and struggle in addiction. Nearly half of Americans have a family member or close friend who is an addict, so it’s possible that we empathize with Mickey because we see ourselves in him, and we want to be better, and do better.

But we also want Ray to win, while recognizing that in this dynamic, both of them simply can’t exist harmoniously. In what effectively becomes a showdown between fatalism and nihilism, one has to be eliminated. For long-time fans of the series, how you suspected it would end, is exactly how it ends; painful and conflicted.

In Ray’s universe, every action he takes has reverberating effects, and the people closest to him feel them the most, most especially his daughter Bridget (Kerris Dorsey), who plays a crucial role in bringing the finale to a close. Like his relationship with his father, Ray’s relationship with his daughter is just as complicated. He’s aware and tries to be anything but like his father, yet the apple doesn’t fall far from the tree. He’s destined to put others in harm’s way. Shifting its location to New York City, it’s a wonder that Ray has yet to willingly find a permanent resting place in the East River, with his family alongside him, given his interminable will to dive into the deepest of ends, in the darkest of nights, using his shrewdness to clean up one hellish mess after another, seemingly subsisting only on serviceable scotch and coffee. Seriously, does Ray ever sit down and eat? A young widow, Bridget somehow retained her sanity and humanity through a tumultuous childhood. “It had to stop. It had to end,” she says to Ray after a devastating final development that may seem to signal that this traumatic familial cycle has finally been broken. But if it hasn’t always been certain whether she wouldn’t succumb to a generational history of violence, “Ray Donovan: The Movie,” clarifies with an exclamation mark. It’s dark and unrelentingly so. Just as quickly as any beloved character draws your sympathy, they rip your heart open. And despite the emotional topsy-turvy, viewers can’t look away. There’s a Nietzschean read of “Ray Donovan” as a character study in what it means to be a man. If “Killing Them Softly’s” Andrew Dominik was to transition to television, “Ray Donovan” is the kind of series he’d probably make. It’s about socioeconomics, the mythology of gender and crime, and suggests that everything in life is a transaction. Despite the title character’s steely exterior, Schreiber paints a handsome portrait of a man bent on exercising extreme self-control, yet who seems to be running in place. Infamous amongst the glitterati, Ray doesn’t necessarily love what he does. He approaches his sleuthing like the scorpion does the frog, as a tough Boston Southie who often seems like he’d rather be working for the victims his clients hire him to eliminate. When it comes to his own life and problems, Ray can’t simply resort to the kind of violence that he utilizes in his professional career. He can’t take a baseball bat to the depression and post-traumatic stress disorder that plagues the Donovan family, rooted in a history of abuse. “I don’t know where to start,” Ray says to therapist Dr. Arthur Amiot (Alan Alda) over the phone.

“Why don’t we start with the fact that you called me,” Amiot responds. “Takes a lot of courage. Why don’t you sit with that.” And there, the healing begins. Or so it seems. But let’s call it progress, as Amiot gains Ray’s trust and opens him up. “PTSD is destructive and kills people,” Amiot says to his stoic patient. “It must be worked on throughout one’s entire life to heal, to forgive people, to forgive yourself.” It is in those moments of self-introspection that the series is most revelatory and captivating. An eighth season would have afforded a deeper dive into the Donovan family’s backstory, which is evidently what the movie is meant to do, giving closure to Schreiber’s title character and the outstanding ensemble around him. But one gets the feeling that there’s much left unsaid and undone. Although it was probably the right time to close the curtains on “Ray Donovan,” as the series had begun spinning a bit in recent seasons after the action moved from the West to the East Coast. As a result, it occasionally drifts, but the character development and strong performances overshadow its weaknesses. After seven seasons, these actors are indistinguishable from the characters they play. Familiarity with the series isn’t mandatory, but it would benefit viewers coming into this universe for the first time. There’s an emotional investment to be made from time spent with this dysfunctional unit trying to reconcile with its dysfunction, which is when “Ray Donovan” is at its best; when it gets messy, digging deep into wounds that haven’t yet scarred. Its volatility is its strength. And while the movie finale may not come in a package that satisfies every diehard fan, it wraps up its compelling portrait of an eccentric working-class family as emotionally chaotic as should be expected; although the specifics still may come as a shock to some.

Grade B

“Ray Donovan: The Movie” premieres Friday, January 14 at 9 p.m. ET on Showtime. Sign Up: Stay on top of the latest breaking film and TV news! Sign up for our Email Newsletters here.