Despite serious illnesses and economic challenges, a middle-class family from Scranton comes together for a difficult Thanksgiving at the youngest daughter's reconverted prewar apartment in lower Manhattan in Stephen Karam's underwhelming new play "The Humans," which is receiving its New York premiere with the Roundabout Theatre Company.

Karam is a genuine Roundabout success story, having premiered two terrific comedic dramas ("Speech & Debate," "Sons of the Prophet") there, just like his colleague Joshua Harmon ("Bad Jews," "Significant Other"). Their plays have invigorated the Roundabout's multi-floor Off-Broadway space, serving as a necessary counterpart to the countless revivals that the company churns out on Broadway.

Devised as a single scene, "The Humans" is a series of portraits of emotionally and physically damaged individuals, such as Erik, who at 60 is out of work, having marriage difficulties, experiencing back pain and taking care of his elderly mother, who is suffering from Alzheimer's; and Erik's 34-year-old daughter Aimee, who just lost her longtime girlfriend and is dealing with a serious stomach condition that has derailed her legal career.

Under the direction of Joe Mantello ("Wicked"), the six-member cast (including Reed Birney, Jayne Houdyshell and Sarah Steele) delivers vulnerable, truthful performances while also handling simultaneous action on the two-story set, overlapping dialogue and many silent pauses.

That being said, "The Humans" is surprisingly empty as a narrative, lacking the twists and wicked humor of Karam's other plays. No climax or resolution occurs. Instead, it just drags along for just under two hours with an overwhelmingly downbeat aura.

If you go: "The Humans" runs through Dec. 27 at the Laura Pels Theatre. 111 W. 46th St., roundabouttheatre.org.