The Barns at Wolf Trap opened last night with a show as warm and inviting as the 200-year-old wooden structures themselves. Bursting with high spirits and versatile young performers, "The Columbine String Quartet Tonight!" sends out its infectious beams like a dose of mid-winter sunshine, the ideal inauguration piece for Wolf Trap's new year round theater.

The place itself, as the Michelin travel guides put it, "merite un detour," which is to say, whether it is on your way or not, you ought to make a point of getting there. The intimate size and weathered interior offer a welcoming atmosphere that feels like meeting an old friend. The sound seems to be uniformly clear and vibrant. Last night, the music had a splendid resonance and with only 380 seats -- extremely comfortable, by the way, no barn benches here -- every member of the audience can have a close connection with the stage.

This first evening turned out to be a real winner, a case of the actuality being far more appealing than the idea on paper. The play has a plot that could be fraught with maudlin episodes, particularly considering that the husband of the first violinist was putting the music together. Inspired by and starring the Primavera String Quartet, "The Columbine String Quartet Tonight!" tells the story of the formation of an all-woman string quartet and its somewhat uneven journey to success.

Thanks to the tight script of Tina Howe, the crisp direction of Andre Gregory, the ingenious staging of musical numbers by Marta Renzi and the pointed music, some original and some arranged by Stanley Silverman, the show works without even a dip in the trite direction. It skips along at a brisk pace consistently engaging, frequently funny and, at times, moving. Its main message is that music means life whatever its form, whatever its language -- pop, art or classical -- and its greatest asset is the Primavera itself.

These four exceptional women are really, in a sense, the message. They sing, they play, they dance, they act, often doing several at the same time. First and foremost classical musicians of the highest order, they won the prestigious Naumberg competition in 1977 and are developing a major reputation in the serious music field. They have a glowing sound and a finely shaped sense of ensemble as the classical exerpts on the program clearly reveal.

At the same time they obviously get a robust enjoyment out of playing popular music. They regularly perform with Frank Sinatra and have appeared on one of his albums. Their enthusiastic renditions of the popular numbers in the show, sung by Silverman and others by such composers as Gershwin and Porter, proved an equal delight. Their singing and dancing, if not on the same level as their playing, still possessed an appealing quality, primarily because they seemed to be having such a good time doing it.

As Silverman points out in the program notes, the quartet simply has no hangup over the gap between high art and popular art. Their answer, he says, is simply "why must there be a choice?" Why, indeed, if one is as talented as this group?

Though all four are quite attractive, each member has a distinctive appeal. First violinist Martha Caplin brings an inner quality that seems to act as the spiritual force within the group. Second violinist Mitsure Tsubota contributes petite Oriental good looks and slight sauciness of manner. The willowy violist Diann Jezurski projects with the animated fierceness of a perfectionist, and cellist Melissa Meell has a vigorous earthiness. These qualities come through both in the playing and acting of the quartet members, lending a dynamic edge to their performance.

Larry Pine, in the role of the friend, admirer and supporter of the quartet -- more or less the play's counterpart of Silverman -- rounded out the cast. His easy manner and genial presence made an excellent foundation for the quartet's high-jinks. The uncomplicated sets of David Mitchell and the simple costumes of Ann Emonts were an effective addition.

The play, a presentation of the Music Theatre Group/Lenox Arts center in conjunction with Wolf Trap, will be repeated tonight at 8.