Mitchell Hébert as Roy Cohn and Sarah Marshall in "Angels in America Part II: Perestroika." (Danisha Crosby)

In Part II of Tony Kushner’s wry masterwork, “Angels in America,” we learn that God has left the building. The befuddled spirits whom the Lord has deserted are reduced to sitting around heaven, trying to pick up signals on a scratchy radio for what they should do next.

They’re as rudderless, it seems, as the stressed-out mortals adrift back on Earth in a scary era of metastasizing disease — and selfishness. A time, we’re advised, of chaos that is badly in need of some messianic intervention, which the angels deem to be supplied in the guise of Prior Walter, a gay New Yorker ravaged by AIDS.

But Prior, in Tom Story’s deeply affecting portrayal, rejects the deus ex machina role: He’s actually far more grounded than these celestial know-nothings, who are supposed to know everything. He just wants to live out what’s left of his life — in, with their grace, a miraculous remission — among people he cares about.

The tale of that simple wish provides a compelling spine for the longer, and yet just as engrossing, second half of Round House Theatre and Olney Theatre Center’s co-production of “Angels.” Kushner’s tapestry portrays marginalized gays, Jews, Mormons and African Americans struggling to survive and find meaningful connection in a 1980s America that offers them little help with either.

Bolstered by some extremely high-caliber performances, director Ryan Rilette picks up with aplomb at Round House where Jason Loewith, who staged Part I, left off. In this half of Kushner’s Pulitzer- and Tony-winning epic, several of the actors, like Story, who laid down exemplary foundations, build marvelously on what has come before. In particular, Kimberly Gilbert, as flaky, drug-addled Harper Pitt, a Mormon wife pushed away by her tormented, closeted gay husband Joe — the excellent Thomas Keegan — comes into her own in Part II, as a woman who gains courage as her dependence on a man is jolted out of her.

Sarah Marshall, too, blossoms here in the role of Joe’s stereotype-defying mother Hannah, whose background suggests unworldliness and suspicion but who is, in fact, open to new ideas and is heart-meltingly compassionate. In a similar vein, Jonathan Bock, playing Prior’s lover Louis, a cerebral if underemployed legal clerk who leaves Prior when the going gets rough (there are a lot of abandonment subplots in “Angels”), gives a persuasive account of Louis as he turns a corner toward responsibility and maturity. And Jon Hudson Odom as Belize, the gay nurse assigned the awful task of ministering to the dying, self-hating Roy Cohn (an at-all-times amusingly deplorable Mitchell Hébert), is downright stellar as the play’s fount of gimlet-eyed wisdom.

Several major threads from the first part (called “Millennium Approaches”) are resolved at luxurious length in the three-hour, ­40-minute second half, all having to do with the deftly developed stories of characters seeking comfort in an America rigidly resisting finding antidotes for their suffering.

This part, titled “Perestroika,” can feel labored as a result of lessons being hammered home: The play is bookended by declarations about a country unmoored from principles that extend beyond materialism and self-promotion. This sense of overkill reveals itself most plainly in the message-laden heaven scene late in the evening. But the sequence in which Story’s Prior answers the call of his visiting angel (a majestically persuasive Dawn Ursula, descending impressively, courtesy of D2 Flying Effects) is in this case seasoned by Rilette and cast with enough humor to reduce archness to a minimum. Instead, we’re kind of tickled to see the actors who’ve been playing such singular roles all night converge at last on the stage as an ethereal chorus, in wings and robes.

Round House and Olney offer such a fully realized serving of Kushner’s epic that you would be inaccurate if you asserted you’ve had the “Angels” experience without seeing both. It’s a big commitment, for sure. But Kushner’s a big thinker.

Angels in America Part II: Perestroika, by Tony Kushner. Directed by Ryan Rilette. Set, James Kronzer; projections, Clint Allen; costumes, Ivania Stack; lighting, York Kennedy; sound, Joshua Horvath; dialects, Zach Campion; fight choreography, Casey Kaleba; flying, D2 Flying Effects; stage manager, Che Wernsman. About 3 hours, 40 minutes. Tickets: $30-$75. Through Oct. 30 at Round House Theatre, 4545 East-West Hwy., Bethesda. Visit or call 240-644-1100.