Talk about having your moment: Masters of Sex writer Steven Levenson wrote the book for Broadway’s new hit Dear Evan Hansen and recently signed on as book writer for Will Ferrell and Kristen Wiig’s new movie musical under producer Marc Platt. With If I Forget, Levenson returns to the Roundabout Theatre Company, which earlier presented his The Language of Trees and The Unavoidable Disappearance of Tom Durnin.

Brilliantly staged and at once funny and deeply unsettling, If I Forget concerns three generations of a Jewish family dealing with the fraught interplay of Holocaust remembrance and their own troubled journeys in modern times. The setting is an upper-middle-class Washington D.C. neighborhood where three adult children have gathered at the family home. Crises abound both global and personal: It’s the summer of 2000 and the Middle East is heading toward a second Intifada as the Oslo Accords fall apart. We see Lou Fischer (Larry Bryggman), a WWII veteran who took part in the liberation of the Dachau concentration camp, watching the news.

Upstairs, Lou’s middle child Michael (Jeremy Shamos) frets as his wife Ellen (Tasha Lawrence) speaks with their teenage daughter, who is in Jerusalem on a Birthright trip that sponsors visits to Israel by young Jews. Michael’s older sister Holly (Kate Walsh, Private Practice), husband Howard (Gary Wilmes) and her teenage son Joey (Seth

Maria Dizzia and Jeremy Shamos in "If I Forget."
Maria Dizzia and Jeremy Shamos in “If I Forget.”
Joan Marcus

Steinberg) live nearby, as does Michael’s younger sister Sharon (Maria Dizzia, Orange Is The New Black). The siblings could be caricatures: Michael is a Jewish Studies scholar whose knowledge has led him to a renunciation of the religion his daughter is just now encountering. Holly is snappy, caustic and smug in her marriage to a successful lawyer, the  picture of well-finished privilege. Sharon is just beginning to find herself, growing close to the Guatemalan family who run a bodega in a building the family owns.

But Levenson is such an expansive and gifted writer – and Sullivan so expert at drawing true-to-life performances from an extraordinary cast – that we never feel trapped in a situation comedy. The Fischer children over the course of this rich, full-length play (a rarity these days) love each other even as they play the push-me-pull-you of siblings with their secrets and agendas, their public posturing and personal disappointments.

At the center is Michael, who is about to publish a take-no-prisoners tract called Forgetting The Holocaust, in which he argues that “the only way we can escape what has essentially become, at this point, a religion and a culture of frankly death and death worship, a culture that finds its meaning and its reason for being in the charnel houses of Europe, the only way we can get past that is if we forget it. Actively. We stop making movies about it and writing books about it, celebrating it, venerating it …”

He’s also, by the way, been recommended for tenure and seems oblivious of the fact that the timing of his new book may prove an obstacle to more than just family unity. Michael’s articulation of the arguments against that Old Time Religion is offset by Lou’s recollection of the events at Dachau, when the Allied Army recoiled in horror at what they discovered inside the gates of the camp and then watched as prisoners who were capable exacted some measure of revenge on their Nazi captors:

“And the Americans, they just watched. We just, we stood and we watched. And we were glad. My God. We were glad. I’m still glad. For you, history is an abstraction. But for us, the ones who survived this century, this long, long century…there are no abstractions anymore.”

There are subplots galore, several of which feel contrived. Yet there’s so much more in If I Forget, so many layers to the challenges these wholly conceived and deeply felt characters confront that it seems unfair to limit discussion of the play to the Holocaust. In a stellar cast, Shamos blazes forward; this gifted actor is giving the performance of his career, making the easily abrasive Michael a near-tragic figure.

Roundabout audiences may feel they’re revisiting the same issues raised by Joshua Harmon’s Bad Jews,  also produced by this company and featuring a central conflict between an intellectually gifted scholar who has rejected his Jewish roots, and a sister who’s immersed in them. But of course these are universal themes – how do we honor our heritage without being enslaved by it? If I Forget takes its title from Psalm 137: If I forget thee, O Jerusalem, let my right hand forget her cunning. This is the play of the season so far. I won’t soon forget it.

In the one-act musical Kid Victory, a teenage boy returns to his Kansas home and family after a year in which he was abducted, raped and romanced by a sick, seductive history teacher. Sounds like fun, yes? It isn’t. It’s a mess, and the disturbing subject is the least of the problems in this show, which opened Wednesday at the Vineyard Theater. I’m not complaining; this invaluable off-Broadway company’s misfires are always as instructive as the string of hits (Avenue Q, the new Broadway transfer Indecent) developed in its grotto theater near Union Square.

Brandon Flynn and Jeffrey Denman in "Kid Victory."
Brandon Flynn and Jeffry Denman in “Kid Victory.”
Carol Rosegg

“Kid Victory” is the handle that Luke Browst (Brandon Flynn), uses in a chat room for like-minded boating enthusiasts on a fantasy site where they build sloops and schooners and race them. It’s where Luke escapes his oppressive, devoutly Christian mother (Karen Ziemba) and passive orthodontist father (Daniel Jenkins), not to mention the girlfriend Suze (Laura Darrell) he’s been having second thoughts about. Michael (Jeffry Denman), a predator who calls himself Yachticus Nine, engages with Luke; flirtation leads to a date and Luke’s abduction to a basement cell where he’s intermittently drugged, shackled to the wall, beaten, sexually assaulted and served up Michael’s engaging history lessons on such subjects as the Vikings’ pre-Columbian encounter with North America.

“He found out where I lived and…took me away. Er…we went away,” Luke says, in one of the more revealing lines.

Staged by Liesl Tommy, the show shifts uneasily between the home where Luke’s parents struggle to make sense of their transformed child, Michael’s basement cell (the shackles are the first things to catch the eye as you enter the theater) and the “Wicker Witch of the West,” a greenery and knick-knack shop run by the empathic Emily (Dee Roscioli), a hippie transplant who befriends Luke. (Clint Ramos’ single set emphasizes the cell at the expense of the other locations.)

Kid Victory is the latest effort by composer John Kander (Cabaret, Chicago) and Greg Pierce, the lyricist with whom he wrote the book. They previously collaborated on another one-act, The Landing, which had its premiere here; Pierce also is the author of Slow Girl, presented at Lincoln Center Theatre. All three works take an audience to shadowed byways on the topography of human experience that most audiences assiduously avoid. In this regard, Pierce would appear to be a good fit for Kander, who with his late partner Fred Ebb created tough-minded musicals about the rise of Nazism and women with a taste for murder. (A production of Chicago is currently the longest-running revival in Broadway history.)

Indeed, one of Kander’s exemplary gifts as a composer is his ability to couch discomfiting, often sordid lyrics in irresistible melodies – high-spirited toe-tappers, razzle-dazzle roof-raisers, mournful ballads. That’s as true with Pierce as it was with Ebb; the Vineyard has presented both the scorching Scottsboro Boys, one of Kander & Ebb’s last collaborations, and these shows by Kander and his new partner.

I’ll go out on a limb here and say that Kander’s music is beautiful and that this amazing composer has been liberated, whether by change of partner or his own intellectual progression, into a more Sondheimian palette of tone and melody. Why on a limb? Because nothing else about Kid Victory makes sense, unless one buys into the unsavory suggestion that sometimes Stockholm Syndrome – in which a prisoner comes to identify with his captor – is just another marker on the road to adulthood.