Back in the 1950s, the northern English seaside resort of Blackpool was filled with variety shows in gilded theaters, end-of-the-pier warblers and sardonic comics hoping to give a few laughs to exhausted factory workers on their “wakes week” vacations. The town was on the showbiz radar: a few performers caught a fast tram to their dreams of stateside stardom. But by the 1970s, Blackpool had begun a near-fatal decline as its core working-class market decamped for Majorca, Spain on new, cheap chartered jets. Proud Blackpool and its stars fell apart together. For what it’s worth, I spent my childhood not far from there and watched it happen. Joan Marcus(Left to right) Leanne Best as Gloria, Ophelia Lovibond as Ruby, Helena Wilson as Jill, and Laura Donnelly as Joan in “The Hills of California.” (Joan Marcus) That tacky town in those two revealing decades make up the rotating setting of Jez Butterworth’s “The Hills of California,” a riveting Broadway show at the Broadhurst Theatre about a Mama Rose of Blackpool’s tacky Golden Mile, a woman named Veronica who runs a tawdry English seaside boarding house with the same blend of care and fury as she raises her four daughters. The ensemble acting in Sam Mendes‘ blistering production from London’s West End is off the charts when it comes to veracity, intensity and the manifestation of how childhood trauma invariably impacts adulthood. And the characters Butterworth forges are so empathetic that I never wanted this three-act show even to end. Or even to pause. Not with everyone in such pain. Joan Marcus(Left to right) Leanne Best as Gloria and Richard Short as Bill in “The Hills of California.” (Joan Marcus) As I write the morning after, I feel like I am still recovering from the level of emotion this thing churned around in me. That’s because Butterworth gives these characters representative magnitude. They matter so much because other streets had other sisters, and other working-class folk like these: Vulnerable women trapped in impossible circumstances, so buffeted by forces they can’t control as to be forced to feed only on themselves, to rip apart the lives of the people they love the most. And yet, the ones who lived in Blackpool got to have fun. They were show people, in their way. As played by Laura Donnelly in a stunner of a performance that’s part a gorgeous Judy Garland and part a raging Medea, Veronica’s mid-1950s days are spent enforcing rules for her guests even as she tries to forge her girls into a harmonizing quartet modeled on the Andrews Sisters. We see the adolescent sisters, played by Nancy Allsop, Nicola Turner, Sophia Ally, and Lara McDonnell, boogie-woogie-boying it on the kitchen table. Joan Marcus(Left to right) Nancy Allsop, Nicola Turner, Sophia Ally, and Lara McDonnell in “The Hills of California.” (Joan Marcus) By the 1970s, three of Veronica’s four adult daughters have gathered in the shabby hotel’s mothballed tiki bar to wait our their worn out mother’s painful death upstairs from cancer. They all have their own scars: virginal Jill (Helena Wilson) has sacrificed her life to care for her mother; Gloria (Leanne Best) carries the bitterness of a mother’s opprobium; Ruby (Ophelia Lovibond) does her best to keep the peace. All three are exquisitely rendered. The younger sisters await the arrival of their oldest sibling, Joan, the one that got away from Blackpool to America, the one who has not stepped a foot back in Lancashire for 20 years. When Joan arrives, and it is one heck of an entrance for one hell of a character, she is played by the same actress as was her mother; distinctly but clearly joined at the hip. By then we know something of what destroyed this family and Veronica’s dreams and, in the scenes set in the 1970s, we witness the consequences. “The Hills of California” is not, of course, the first play wherein traumatized adult siblings gather as a parent dies to relitigate their childhoods. Here, though, it’s not about who gets what because these sisters were taught that what mattered was experiential — the ability to live in and through a song. And, obviously, this is not the only play where a pushy stage mom implants her own dreams and frustrations on the innards of her kids. There’s a conscious homage to genre and even a certain overwrought theatricality. Blackpool is a populist resort and a similar streak runs through this play. As, poetically, it should. Joan Marcus(Left to right) Laura Donnelly and Lara McDonnell in “The Hills of California.” (Joan Marcus) But Butterworth is such an extraordinary writer that this epic play goes further. Similarly to the musical “Tommy,” “Hills” examines the post-war absence of fathers and the gray emotional inaccessibility of 1950s British men scarred by war. The males in the play, such as Bryan Dick’s comic and Richard Lumsden’s pianist, witness much but do nothing. There’s no Herbie, as in “Gypsy,” to soften these teenaged girls’ lives. And with the help of set designer Rob Howell, who creates a warren of ascendant staircases as if this were a Conor McPherson or Eugene O’Neill hell scape, booze-soaked and all, Mendes’ relentless direction dives determinedly into existential matters. Most of all, though, “The Hills of California” is about the peaks and valleys of Joan, every bit as compelling a character as Johnny “Rooster” Byron in Butterworth’s “Jerusalem,” and, as with that comparably magnificent 2008 play, manifested by a phenomenal performer. We see the aggressor become the victim, the operator morph into the operated upon. We see a child who must remove herself from her mother, for she has become her, and yet who, really, can actually manage to do that?  Not the women of Blackpool, that’s for sure.