Much is made these days of "serious" musicals of operatic ambition, like The Phantom of the Opera or Miss Saigon. Personally, I have found these shows largely unconvincing. The stage craft is superb, if you go for that kind of thing. But there always seems something too slick and calculated at the core of the endeavor. As for the music, I get crescendo fatigue. I don't feel moved; I feel bombasted.

Blood Brothers, currently on the boards at Carlone's, is a serious musical as well, but utterly different in mood, scale and conviction.

Blood Brothers is a fable, complete with a Mephistophelian narrator (C. Patrick Gendusa) who speaks in rhymed verse. It is primarily about social class -- though, as with all vital works of art, many other themes and ideas orbit around this central concern.

Mrs. Johnstone (Ann Casey) is a working-class lady in London. She gets wooed, pregnant, married and left flat -- with a brood of children and no way to pay the bills. She finds work as a cleaning lady for an upper-middle-class housewife, Mrs. Lyons (Leslie Giglio).

In a deft little scene, Mrs. Johnstone compliments her employer on her big, beautiful house, only to receive the melancholy reply that the house was purchased with children in mind, but that Mrs. Lyons can't have any. Imagine, says Mrs. Johnstone, "and I get pregnant if someone shakes my hand."

In fact, Mrs. Johnstone is pregnant yet once again, and when she blanches at the idea of one more mouth to feed, the doctor corrects her: "Mouths. Plural." She's going to have twins.

Mrs. Lyons cajoles her maid into giving her one of the children to raise as her own and the women swear a vow of secrecy. Mrs. Lyons then fakes a pregnancy (her husband is away on an extended business sojourn in a foreign land). When the babies are born, Mrs. Lyons picks one and takes it home. According to the arrangement, Mrs. Johnstone is to watch her son grow up from her vantage point as cleaning woman. But Mrs. Lyons soon grows jealous and dismisses her on the pretext that she is no longer tending to her work. When Mrs. Johnstone threatens to take the baby with her, Mrs. Lyons says she will turn her in to the police for selling her child.

Years pass. And fate, which hangs heavy over this drama, intercedes. When he is 7, the rich twin, Eddie (Jonathan Frick), wanders down to a bad neighborhood, where he meets and befriends Mickey (Nic Young), who is (though neither know it) his twin brother. When they learn they have the same birthday, they perform a little ceremony and declare themselves blood brothers.

The play follows their parallel lives. One brother develops a "posh" accent and receives an education, while the other is marked with all the disadvantages of his upbringing.

This simple fable is given depth by the nature of the characters. Mickey (the poor twin), for instance, is shy and awkward around his childhood girlfriend, Linda (Jennifer Campbell), and needs a shove from seemingly more introverted Eddie (the rich twin) to make him propose to her. Meanwhile, Eddie is not the least bit snooty and, in fact, genuinely loves his raffish, forbidden friends.

In fact, in many ways, "poor little rich boy" Eddie is the most poignant character in the play -- as is evident in Jonathan Frick's extraordinarily sensitive and honest performance.

One of the great challenges of Blood Brothers is the long, crucial segment in which grown-up actors play children. And this is the major stumbling block in Jonne Dendinger's otherwise admirable production. Dressing the poor kids like Dickensian ragamuffins with stage paint dirt on their faces doesn't aim the actors in a subtle direction. Neither the effects of class nor the exuberance of childhood are made more vividly real by being "writ so large." And one finds it hard to believe that Mrs. Johnstone, no matter how dire her straits, would allow her offspring to sink to that level.

But speaking of that irrepressible, star-crossed lady, the irrepressible Anne Casey steps into the role like it was made for her; the last chorus of her last song, sung over the corpses of her sons, vibrates in your mind and heart long after the house lights have come up.

The sets (uncredited) are simple but effective clusters of props against a background of gray brick, which serves both for urban squalor and upscale interior. Director Dendinger conducts the four-piece band from the keyboard.

Most of the fare at dinner theaters seems to come from the dessert table, but Blood Brothers is more like an entree: spicy, satisfying and not too sweet. 8 p.m. Friday-Saturday, 2 p.m.

Sunday, through April 8Directed by Jonne Dendinger Carlone's Dinner Theatre, 100 N. Labarre Road, 838-9906