It’s apropos, then, that urban cowboy Tracy Letts has set his latest play—one that all but flattens the premieres that have appeared on Chicago stages in the last few years—among the lonely, tumbleweed-strewn flatlands of Oklahoma. It’s unclear why this generation of new dramatists eschews denizens of the decaying Middle West in favor of, among other things, trivial savants and comic-book heroes. But keep your eyes peeled in years to come. August: Osage County is the kind of play that inspires imitators.

It’s present day in a three-story American house, the elderly owner of which has just committed a rather casual suicide. Our central concern is the clan he’s left behind: a pill-popping sex buzzard of a wife, three adult daughters and a few nagging in-laws. To reveal even a sentence worth’s more of plot would be to unspool the whole creepy yarn, but by now you’ve probably guessed that daddy left a few secrets behind and, like any deceased parent, he saddled his kids with a haunted house.

Letts’s hysteric melodrama is notable for its architecture (classic as a Cadillac); its airtight flow of info (you’ll still be guessing into the third hour); and its daring salt-shaker dialogue (the cynical heroine on “the Greatest Generation”: “What makes them so great? Because they were poor and hated Nazis? Who doesn’t fucking hate Nazis?”).

But it’s the advancement of familiar themes that sets August apart. The childhood home–as–abattoir is nothing new. Yet while scoping the oft-tread territory of preceding American playwrights—Just look at what my parents did to me—Letts stares in both directions for a full-bodied generational clash. Perhaps we weren’t so great for them, either, the play posits, and maybe becoming them is our punishment. This knowing culpability, along with the playwright’s bayonet wit, is what makes him an upgrade on a similarly spirited dramatist. (With apologies to a Steppenwolf literary forefather, Letts is my Shepard. I shall not want.)

While more than robust at 13 characters, the play is ultimately a showdown between two tough pioneer dames. Dunagan plays the dotty mom on the decline, while Morton nearly stops time as her defensive, raging daughter on the rise. Steppenwolf’s main stage, like that blasted three-story house, is hardly big enough for the both of them. (Their gaunt, pallid faces, by the way, are frighteningly well lit by Ann G. Wrightson.)

The ensemble is so fine and so large that listing them is less economical than singling out casting director Erica Daniels—her work, especially in appropriating Letts’s born-loser men, is like cold fusion—and director Shapiro. In the past, Shapiro’s sterling work has contained a certain degree of flash. Here she’s close to invisible. (A shocking, postfuneral dinner scene—with 11 guests—is her Ben-Hur chariot race.)

August isn’t quite flawless. In the final act, the thing seems to end about three times; the metaphors can get overripe (hate-spewing ma has cancer of the mouth); and Ian Barford’s lumbering oaf, while excellently played, feels less slow than a little underwritten. And a few production details—mainly over-pronounced kitsch on Todd Rosenthal’s set—betray the authenticity just a hair. On the other hand, while no hairdresser is credited, the women’s highway I-35 near-mullets border on cinema vérité.

In the meantime, Letts does what no Midwestern dramatist has done to date. With passive aggression and self-denial made violently manifest, he bucks the repressed but inoffensive romanticism of Inge’s Kansas and the poetic but inactive yearning of Williams’s St. Louis. Instead, he offers a prairie-dwelling anti-Lear, one in which three orphaned daughters run like hell away from the throne for fear of inheriting it.

At once traditional and progressive, August offers a new lesson in American playwriting: If a play’s soil is parched, it’s probably fertile.—Christopher Piatt