The Opera Theatre of Northern Virginia presented a world premiere of Seymour Barab's "Who Am I?" Saturday evening at the Thomas Jefferson Community Theatre in Arlington.

Barab's tale of princes and princesses teaches a modern moral. "It's a very important subject, the subject of prejudice or bigotry," Barab said from the stage, in answer to a question after the performance. "It might be lost on the adults, but I hope the children get it." The median age of the audience probably did not exceed 7 or 8 years old.

Barab's desire to reach children led him to use relatively simple plot devices and musical structures, which, judging from the enthusiastic response of the children, did the trick. What might have seemed overdone, or overly simplified, in a show geared toward an adult audience, was appropriate for youngsters.

The story follows members of the court of a fantasy land, Magnolia, in their trip to another fantasy land, Mythica, for the wedding of the princess of Magnolia and the prince of Mythica. The homely handmaiden to the princess contrives to take the bride's place at the wedding because she has always felt angry, unloved and uncomfortable with herself. But she can no more change her status in life than change her name, Venus Flytrap, and is found to be an impostor. She learns to be happy as herself when the Magnolian palace guard, Ragweed, convinces her that he likes her just the way she is.

Soprano Myung Kim stood out in her assured performance of Princess Orchid. She was lucky to have had the most beautiful parts of the opera written for her: soothing lyric lines that quickly identified her as a sympathetic character. Soprano Laurie Nelson worked effectively with the more brash material provided for her role as Venus.

That's just the way Barab wanted it. "If I expressed musically that the princess is more lyrical and Venus was more crude, then all the better," Barab said.

The entire cast sang with precise and clear diction, so important for the under-10 crowd, which needed to know exactly what was being sung as well as said. The acting tended toward large gestures, but not self-consciously so.

John Edward Niles, the company's artistic director, conducted the National Capital Chamber Players in the pit through an evenly paced reading of the score that left plenty of room for the singers to be heard. Under Niles' direction, particularly in the scene changes, the music proved to be tightly constructed in a conservative style.