WITH ITS accomplished and absorbing production of "Johnny Bull," Horizons Theater has another hit on its hands. The bittersweet story of Iris, an English slum girl imported to America as a G.I.'s war bride, "Johnny Bull" is the second in a trilogy based on English playwright Kathleen Betsko's experiences as an immigrant in the '50s.

Waiflike Iris shaped her rosy, rhinestone-studded vision of America watching Doris Day movies and flipping through movie magazines, and she's in for a rude awakening. Dressed to impress in a gaudy green dress, she steps into her New World: a clean but shabby shack in Willard Patch, Pennsylvania, a hard luck coal-mining town somewhere between post-war England and Hollywood.

Iris gets a hostile reception from husband Joe Kovac's family, Hungarian immigrants who confront her with a platter of pigs' feet and bluntly dub her "Johnny Bull," lower-class slang for a Britisher. The newcomer soon realizes she'll have to fend for herself -- her good-natured lug of a husband is an overgrown child in fear of his bigoted coalminer father -- and she is left to learn about women's work, the lion's share of which is shoring up the crumbling egos of the menfolk.

But while she's looking for a way out -- even the local Woolworth's seems an enticing escape -- resilient Iris gradually assimilates herself, and she discovers some kinship with the Kovac women, too, stirring up a bit of nascent feminism in silently suffering mama Marie.

Betsko's Iris remains a chirpy good sport about her sorry situation, and though poverty holds her hostage to miserable conditions, she doesn't go around wringing her hands and moaning. "It wasn't anybody's fault," she confides in one of her candid narrative asides, realizing the joke is on her.

Betsko's play tends to ramble toward the end, with several false-alarm endings and a few too many careworn cliche's lying about, but overall "Johnny Bull" is a fine, life-affirming evening. Director Dorothy Neumann sensitively balances humor and pathos and, as always, shows a keen eye for telling detail.

As the plucky English sparrow Iris, Barbara Klein frequently recalls (favorably) a young, energetic Liza Minelli. Barbara Rappaport is affecting as embittered and battle-weary Marie, who warms up to and is warmed by her daughter-in-law. As Joe, Brian Hemmingsen has yet another of his trademark sensitive prole roles, and once again fills the part admirably. Matthew Cooper's realistic shack is another instance of Horizons' imaginative use of its relatively small space.

JOHNNY BULL -- At Horizons Theater (at Grace Episcopal Church, 1041 Wisconsin Ave. NW) through May 18.