It's not hard to find the new Castle Performing Arts Center, a renovated armory proudly calling itself "the first professional theater in Hyattsville." It is the only castle in town -- or at least the only one on the east side of U.S. 1. For its first production (with the final performances next weekend), the Castle is presenting the world premiere of "Huckleberry Finn," an opera by Martin Mangold, director of the Opera Theatre department at the University of Maryland.

Mangold composed the music and (with considerable assistance from Mark Twain) the libretto. He also conducts and plays the cello in the four-piece orchestra, and has shaped the classic novel into an enjoyable show that offers two hours of high energy on a low budget.

The show stands midway between opera and Broadway. It has no spoken dialogue, but leans slightly toward Broadway, at least in this production. In structure and flavor, it is not unlike Bernstein's "Candide," but can't compare with the lavish treatment "Candide" received at Arena Stage. In one sense, Mangold is more satisfactory than Bernstein, who raises cosmic questions only to substitute lavish production numbers for satisfactory answers. "Huckleberry Finn" does not try to be cosmic or lavish, and fulfills its modest ambitions quite satisfactorily.

Mark Twain's homespun flavor is captured and the rudiments of his plot are faithfully sketched, particularly in Act 2, when Tom Sawyer comes on the scene and engineers the melodramatic rescue of Jim, the runaway slave. But the plot serves mainly as a sort of clothesline on which to hang highlights: Huck's father suffering from the d.t.'s; the episode of the Duke and the Dauphin (with a hilarious pastiche of the soliloquy from "Hamlet"); Huck's decision that he will be a criminal (helping a slave to escape). The music has no show-stopping tunes, but is solidly theatrical throughout, moving the action along, heightening its emotional impact and expanding effectively into a fine lyricism at climactic moments.

The cast has two standout performers, Reginald Evans (the best voice in the production) as Jim, and Stanley Noel Dunn in a variety of mostly villainous roles, including Huck's father and the Duke. These two are responsible for the evening's most memorable moments, but the whole cast is generally well-chosen. Richard Troxell, in the title role, has to look both like 15-year-old Huck and a 35-year-old businessman, switching from one to the other on stage -- mostly by taking off or putting on shoes. He manages the trick neatly and sings with a decent if not outstanding Broadway voice. J.R. Hontz is vocally and theatrically effective as Tom Sawyer. Anne Stovall-Charrier plays the mature women in the story and Deborah Madsen the ingenues, both in fine style.

The Castle's auditorium is comfortable, air-conditioned and well-laid out, with a fine proscenium but not much space for lavish scenic effects. In this production, a unit set made up mostly of planks and crates serves as the Mississippi River and various places along its banks. The acoustics are clear and a bit hard-edged; almost all the words came through in the solo singing, but there was less clarity in the ensemble numbers.