Washington Stage Guild’s three-part presentation of George Bernard Shaw’s Back to Methuselah is one of only a handful of professional stagings the witheringly long, dauntingly strange “metabiological pentateuch”—five plays set over a period of 36,000 years—has ever had. Shaw is WSG’s patron saint, and there’s something admirably perverse about the 29-year-old outfit’s nerdy completism, given that Shaw himself regarded Methuselah onstage as a commercially hopeless enterprise. (He expected his audience to buy the script, first published in 1922, which they did.) WSG performed the first third a year ago, and has the conclusion on deck for early 2016. The current, middle installment consists of two beard-stroking comedies with a common cast, The Thing Happens and The Tragedy of an Elderly Gentleman. Let it never be said that Mr. Shaw, the novelist-turned-critic-turned-playwright responsible for The Simpleton of the Unexpected Isles and The Shewing-Up of Blanco Posnet, didn’t have a knack for titles.

This pair would work just as well on the radio. (Indeed, the BBC did a radio adaptation of the whole, five-part deal as recently as 1958.) Shirong Gu’s set design is minimal. It’s most memorable element is a brain in a jar that WSG has had at least since its 2011 production of Shaw’s futuristic The Apple Cart. That pickled brain returns in The Thing Happens, which takes place in 2170. The British Empire is still an empire, but it’s based in Baghdad now. It has an elected figurehead—the red-faced Conrad Feininger, who somehow brings whimsy and gravitas to every role—but all the important decisions are made by hired advisors from China or Africa, as Britons have been deemed too immature to govern. Jacob Yeh plays the president’s unflappable Chinese counselor, Confucius. Yeh, a solid comic actor, is Asian-American. Laura Giannarelli, who plays the Minister of Health—a “negress” in Shaw’s text, which includes a rant against “the vulgar color prejudice that disparages her great ability”—is white.

The dense plot concerns the revelation that the Archbishop of York (sturdy WSG regular Brit Herring) is nearly 300 years old, despite looking like a fit fortysomething. Three centuries is the age to which we must aspire if the human race is ever to become civilized, he argues. The sputtering Accountant General (Michael Avolio) is less amazed by this physiological miracle than alarmed that its beneficiary has overdrawn his government pension five or sixfold. (This is a society with a retirement age of 40, which sounds pretty good until you realize it’s also one wherein the men have rediscovered leggings.) “You do not comprehend the relationship between income and production,” the Archbishop chides the bean-counter. Zing! This is Rand Paul’s favorite Shaw.

Part 2’s part two, The Tragedy of an Elderly Gentleman, unfolds in 3000 A.D. Vincent Clark plays the “elderly” gentleman of about 65, whom the secret of longevity has eluded. Lost in a colony of benevolent long-livers—more evolved humans represented by Stephanie Schmalzle’s Zoo, a chirpy adolescent of 56 assigned to be his chaperone—the gentleman finds that his reliance on idioms that the long-lived have abandoned, and his outmoded notions of propriety, make it nearly impossible for him to be understood. The voracious mutability of language is a reliable source of comedy in time-travel stories. It also explains why a lot Shaw’s jokes don’t exactly kill anymore. (Plenty still do, but not so much the ones in Back to Methuselah.)

WSC founder Bill Largess and his company of regulars (only Yeh and Schmalzle are new to the troupe) have taken an earnest, honorable swing at reanimating Shaw’s clunky philosophical treatise on humankind’s destiny and folly—or the 40 percent of it included in Part 2, anyway. For all its grand concepts, the production is at its most involving when its focus shrinks to two people whose common tongue has been made foreign by the passage of time. That’s a problem artists trying to wring laughs from a century-old futuristic satire can easily understand.

If Back to Methuselah, Part 2 sounds like a tough sell from a famous brand, try Kid Victory, a world premiere musical about abduction, captivity, and kid-rape from veteran composer John Kander. The 87-year-old Tony, Emmy, and Grammy winner is famous for Cabaret and Chicago, among the many other shows he created with Fred Ebb, who died in 2004. Kid Victory is the second on which Kander has collaborated with Greg Pierce, a playwright and short-story writer 51 years his junior.

The result is a grim but surprisingly substantial drama too frequently interrupted by mediocre songs that don’t reveal character or advance the story. One of them is called “Lawn.” Another one is “You Are the Marble.” Performed sans intermission, Kid Victory clocks in at a hair under two hours. Cutting a half-dozen of its 17 numbers, particularly the deadweight ones with which the show is regrettably front-loaded, would help. This is not a world in which you’ll want to linger, despite the strength of the book and the performances—particularly an extraordinary turn from Jake Winn, the youthful-looking Tisch school graduate in the title role.

Winn’s Luke is a shy, slight 17-year-old trying to reacclimate to life in his Kansas town after his abduction and prolonged captivity. His harrowing ordeal, the specifics of which are revealed only gradually, have left him even more alienated from his parents, his girlfriend, and their friends from church than he was already. The show is not kind in its depiction of Christians, whom it implies made Luke vulnerable through their intolerance. But Luke, like the show around him, never gives them a chance to accept him. As Emily, a genial hippie who hires Luke to help out at her failing garden-supply store, Sarah Litzsinger contributes some desperately needed humor (and gets two of the better songs, “People Like Us” and “The Last Thing He Needs”). Luke’s shrill mother—who’s just “Mom” in the script, for all of Christiane Noll’s efforts to give her an inner life—is instantly suspicious.

“Help Me Understand,” sung by Bobby Smith in his one scene as the police detective trying to locate Luke’s attacker, is another missed opportunity, stopping the plot for three minutes without telling us anything about the guy singing it. Luke’s fraught attempt at consensual sex, via a Grindr-like app called Matchstick, tees up a tap-dancing number called “Matchstick Men.” In its sheer incongruity, it offers a peek into Luke’s fragmented brain, something too few of these songs do, but it still feels tasteless. I don’t know enough about tap dancing to know whether trying to use it to express the overwhelming and contradictory emotions of an abduction and serial-rape survivor is an inherently stupid idea, but I have my suspicions.

Seen in flashback, Luke’s budding friendship with his eventual abductor (Jeffry Denman, doing strong work in a loathsome part) is frighteningly believable. Pierce and Kander’s sensitivity to the way in which victims of sexual abuse can be made to feel responsible for their own suffering is the fulcrum of insight that makes Kid Victory as tough to dismiss as it is to recommend. This story is nothing to sing about, but that doesn’t mean it shouldn’t be told.

Washington Stage Guild, 900 Massachusetts Ave. NW. $40-50. (240) 582-0050. stageguild.org.

Signature Theatre, 4200 Campbell Ave., Arlington. $29-94. (703) 820-9771. signature-theatre.org.