August: Osage County

With its stagebound roots and top-notch ensemble cast, August: Osage County is quite an acting showcase.

There aren’t any big action set pieces or special effects, so it’s up to the performers and the script — adapted by playwright Tracy Letts — to convey this dark comedy about a dysfunctional family that’s filled with rich characters and sharp dialogue.

Most of those characters are women in the Weston family, who stage an impromptu reunion following a family tragedy at the rural Oklahoma house of Violet (Meryl Streep), a cancer survivor whose addiction to pills has made her loud, stubborn and thoroughly unpleasant.

That attitude filters through the rest of the family, including her daughters Barbara (Julia Roberts), Ivy (Julianne Nicholson) and Karen (Juliette Lewis), who carry plenty of relationship baggage. Likewise Violet’s sister (Margo Martindale), who constantly throws verbal jabs at her loyal husband (Chris Cooper) and their neurotic son (Benedict Cumberbatch).

As more folks arrive, the tension gradually escalates in the sweltering Oklahoma summer, turning the house into more of an insane asylum. One by one, dark secrets are revealed that cause the weekend to turn ugly and the family to crumble.

At its core, the film is an unsettling relationship drama in which the bickering might seem repetitive, but it confronts deep-seeded issues without sugarcoating them.

Letts (Killer Joe) and director John Wells (The Company Men) keep most of the action confined to one location, and don’t make much of an effort to free the material from its stagebound roots.

Still, the performances help to smooth out the rough spots and melodramatic detours, and there are plenty of powerful character-driven moments, such as an uncomfortable and unforgettable extended sequence at the dinner table.

Streep’s performance is more than abrasive histrionics. Rather, she digs deep and finds sympathy is a bitter matriarch whose drug-addicted defiance masks an inner vulnerability. The cast also includes solid work from Roberts, Martindale, Cooper and Sam Shepard in a small but pivotal role.

August: Osage County evokes rural Americana, warts and all, while channeling Tennessee Williams and Eugene O’Neill. While it’s rarely fun to watch a family sort out its dirty laundry in such graphic detail, fortunately there’s a pervasive acerbic humor that helps to compensate for what could have turned into a train wreck.

Rated R, 121 minutes.