THEATER REVIEW : Good Things Come in Small Packages : * ‘Mud’ tells the story of a woman who wants out of an Appalachian shack--and an unfulfilling existence.

American playwrights are trying to think large these days. If the plays are large enough, like Tony Kushner’s “Angels in America” or Robert Schenkkan’s “The Kentucky Cycle,” they make it to Broadway. It’s one way to think, but it’s not for everybody. It’s certainly not for Maria Irene Fornes.

From the headiest days of the ‘60s up to the present, Fornes has thought small. There are a few exceptions, like the sprawling “Fefu and Her Friends” and some of her Padua Hills festival plays that used big outdoor landscapes for a stage. Otherwise, Fornes has become perhaps our most brilliant miniaturist stage writer.

“Mud,” at the Alliance Theatre, is one of her most brilliant miniatures. Her outline is achingly simple. Mae (Laura Leigh Hughes) wants to get out of the Appalachian shack she shares with Lloyd (Scott Allan Campbell). She also wants to get away from Lloyd, whom her father, now dead, brought home when she was young. Lloyd is almost like a brother, but he also uses her for his sexual gratification (at first, Hughes’ Mae suggests that she doesn’t entirely mind).

Since her mother is also long dead, Mae has nothing else left to call home, and designer Matthew C. Jacobs drives the point home with a shack that appears as if it were aborted in mid-construction. Who could stand living in a house with a skeleton of 2 by 4s for walls?

The only way to get a real home, Mae reckons, is learning the three Rs. But her reading isn’t good enough to understand the prescription for Lloyd’s medication (he has every disease known in the mountains, and he’s also impotent). The only fella nearby who can read this stuff is Henry (Elkanah J. Burns).

Fornes’ world is so small that the entry of one character is like a tidal wave. Lloyd never quite recovers from Henry, who moves into the shack. Mae never does either: She wraps her legs around Henry and says in her sexiest voice, “I want your mind.”

Fornes can fill a whole scene with a line like this. Her play moves along relentlessly with one brief scene after another, the actors frozen in action at each scene’s end like a snapshot. In this way, director Lora Zane and light designer Robert W. Zentis create a series of Expressionist stage pictures. With the audience viewing the stage on the north and south ends of the Alliance space, the effect is of watching creatures under a glass.

A few problems arise here. Zentis’ lights are TV-studio bright during scenes, tending to wash out the moods the actors work hard to achieve. And because of the semi-arena atmosphere, any audience (such as Saturday’s) that tends to guffaw at some of Lloyd’s more monkey-like antics can ruin the mood even further.

This can also egg on an actor in the wrong direction, and Campbell almost loses it as Lloyd. Mae is in this isolated island of a place with her books, and Lloyd is a sluggish Caliban, so Fornes is slightly toying with “The Tempest,” minus the redemption. Lloyd is thus a sad creature, helpless, a hulk without a brain, and therefore dangerous. He’s no clown.

Campbell knows this, but he’s not helped, for instance, by audience members who audibly groan when his Lloyd drools. Burns gets some of the same reception when his Henry becomes a fat, flopping invalid after an accident. Both actors admirably push the physical limits and ignore poor audience behavior. A good night’s work.

Hughes’ work ethic is no less rigid, even though she hasn’t found an Appalachian accent. She’s the kind of actor who works from the feet up rather than the head down, and has a wonderful way of turning Fornes’ phrases into razor-edged verse. It’s felt, not declamatory, the right pitch for a fine miniature.

WHERE AND WHEN

What: “Mud.”

Location: Alliance Theatre, 3204 W. Magnolia Blvd., Burbank.

Hours: 8 p.m. Thursdays through Saturdays. Closes April 30.

Price: $15.

Call: (818) 566-7935.