The formula for a family-reunion play goes like this: Multiple generations of a clan get together for a holiday, air their dirty laundry at dinner, start fighting over dessert and at the end of the day are weary of battle. Stephen Karam’s warm-hearted play “The Humans ” follows the formula, but only to the point of exposing everybody’s secrets. Instead of erupting in bitter hatred, Karam’s characters respond to these revelations with deep love.  That alone should keep this lovely play, an Off Broadway transfer, running in its inviting new Broadway house until kingdom come.  

You can discover a lot about the Blake family in David Zinn’s evocative set and Justin Townsend’s suggestive lighting, which indicate right off the bat that some dark cloud is coming this way.  Ostensibly, the setting is the Manhattan flat of Brigid Blake (Sarah Steele, so very likable), the baby of the family, and her live-in boyfriend, Richard Saad (Arian Moayed, ditto).

But in visual terms, there are clues of unforeseen divisiveness in store for this lower-middle-class Irish family, which has made the long trek from Scranton for this special occasion. What they find is a cement-block basement apartment in Chinatown, stacked on two levels, each as ugly as the other, and connected by a spiral staircase. The only window overlooks a brick-lined alley filled with cigarette butts. (It’s an interior courtyard, Brigid insists.) The lights keep going off, adding to the gloomy darkness.  And the elderly Chinese woman who lives upstairs keeps dropping impossibly heavy weights on the floor. Are these signs that this family has literally bottomed out?

The sheer logistics of having to run up and down a staircase to prepare and serve an elaborate Thanksgiving meal is daunting, but director Joe Mantello (“Wicked,” the upcoming “Blackbird”) doesn’t miss any opportunity to make it funny as well. In fact, the early parts of the play are extensively mined for laughter by a wonderful cast, starting with the great Jayne Houdyshell.

Like any doting mother, Deirdre Blake (Houdyshell) arrives with mountains of food and a mouthful of veiled criticisms about her daughter’s lifestyle, choice of mate, present job and future plans. (“Marriage can help you weather a storm” is one of her more subtle nudges.) But right off the bat, the theme of her Mom-isms is money, a subject that is raised again and again by every member of the family. “Man, it never ends,” says Dad. “Mortgage, car payments, internet, our dishwasher just gave out.”

The head of the family, Erik Blake, is played by the invaluable Reed Birney as a loving father, albeit one with a lot on his mind that he hopes no one will notice. But his mental absences, as he stares out the window at the brick alley or simply pauses and lets his thoughts wander far, far away, are a sure giveaway that something is seriously troubling him. And once in a while, he lets his depression creep out: “Whatever gifts God’s given us, in the end, no matter who you are, everything you have, goes.” If you study his face long enough, Birney can bring you to tears without saying a word.

Elder daughter Aimee (Cassie Beck) is a successful Philadelphia lawyer, but she’s suffering a bout of colitis today, so excuse her if she’s not in top form. Actually, she’s in great shape in Beck’s smooth and subtle performance, relying on her terrific sense of wry humor to carry her up and down the stairs.

Suffering from advanced dementia, Erik’s mother, Fiona “Momo” Blake (Lauren Klein, in admirable control of this difficult role), came to this party in a wheelchair. That in itself involves a great deal of maneuvering to get her to the bathroom. But monitoring her speech is another matter, and there’s something very sad and slightly ominous about her mournful and repetitive outbursts. (“There’s no going back…. there’s no going back.”)

Each and every character is enormously appealing, and Karam takes care to reveal their guarded secrets with great tenderness, just as Mantello’s directorial hand gently advances the play from comedy to tragedy. The revelations of weakness in this close-knit family are not entirely unexpected — lost loves, failed jobs, depression, money troubles, health problems, unpardonable misjudgments and the overwhelming pain of grief and regret.

The big question, of course, is whether the Blakes can survive after this emotional night. Karam doesn’t make it easy for them — or us — and the ambiguous ending seems to tilt toward darkness. But don’t bet on it. Karam has also taken great care to show us that the members of this family truly love one another, and is there a more powerful force than that?

Broadway Review: ‘The Humans’

Helen Hayes Theater; 410 seats; $99 top. Opened Feb. 18, 2016. Reviewed Feb. 10. Running time: <strong>ONE HOUR, 35 MIN.</strong>

  • Production: A presentation by Scott Rudin, Barry Diller, Roundabout Theater Company, Fox Theatricals, James L. Nederlander, Terry Allen Kramer, Roy Furman, Daryl Roth, Jon B. Platt, Eli Bush, Broadway Across America, Jack Lane, Barbara Whitman, Jay Alix & Una Jackman, Scott M. Delman, Sonia Friedman, Amanda Lipitz, Peter May, Stephanie P. McClelland, Lauren Stein, and The Shubert Organization, with executive producers Joey Parnes, Sue Wagner, and John Johnson, of the Roundabout Theater Company production of a play in one act by Stephan Karam.
  • Crew: Directed by Joe Mantello. Set, David Zinn; costumes, Sarah Laux; lighting, Justin Townsend; sound, Fitz Patton; production stage manager, William Joseph Barnes.
  • Cast: Cassie Beck, Reed Birney, Jayne Houdyshell, Lauren Klein, Arian Moayed, Sara Steele.