THE YEOMEN OF THE GUARD is a Gilbert and Sullivan curveball. It skips along in familiar G & S style: the mistaken identities, the thwarted romances, the brutally clever patter, all set to a jolly, stirring score. Yet throughout the operetta there runs an uncharacteristic current of grandeur and sobriety--just when the final scene seems to be resolving itself with happy Gilbertian expedience, the leading character staggers onto the stage and dies a prolonged, hideous death.

Thus, the Harvard Gilbert and Sullivan Players have undertaken an ambitious project, for the usual pitfalls of light Gilbert and Sullivan comedy--convoluted dialogue, supersonic lyrics, labyrinthine crowd scenes--are compounded by the anomalous need for simple pathos. They have overcome the dual difficulties of this operetta in a cautious, straightforward production of Yeomen that is both delightful and moving.

A sturdy core of talented principals proves Yeomen's most valuable asset. Foremost among them is a new face: freshman Erica Zabusky. As Phoebe Meryll, who pines for the condemned Colonel Fairfax while fighting off the advances of his repulsive jailer Wilfred Shadbolt, Zabusky steals every scene she plays. She admirably avoids a problem that bogs down several of the other players: she is at ease and unselfconscious with Gilbert's archaic ods-bodkins-laced dialogue that so easily calls clumsy attention to itself. Her pure, clear mezzo-soprano enchants and, although her flirting with Colonel Fairfax gets her nowhere with him, she has the audience in her pocket.

As Colonel Fairfax, Donald Hovey also stands out. An unusually complex role among Gilbert and Sullivan leading tenors, Fairfax begins as a thoroughly sympathetic character. But by the end of the operetta, he becomes a callous rake, and his marriage to the strolling singer Elsie Maynard leaves two characters heart-broken: Phoebe and Jack Point, the jester who loves Elsie.

Hovey handles this transformation prudently, choosing not to act out a drastic change of character, instead letting the circumstances around him shape his metamorphosis. His easy command of Gilbert's dialogue renders his earnest, deadpan performance natural and often slyly comical. Hovey uses his strong, sweet tenor to a similar end, mocking ever so slightly his heartwrenchingly serious solos.

In the vocally demanding role of the minstrel Elsie, Lisa Sheldon is convincing. Though polished and powerful, her soprano unfortunately lapses occasionally into an operatic ardor and intensity out of place in a light opera at the tiny Agassiz Theater. Her enunciation is murky, at times, with the result that she swallows many of Gilbert's swifter lyrics. Still, her opening duet with Jack Point "I Have a Song to Sing O" is the operetta's high point: sorrowful, simple, and affecting.

G&S ROMANTIC LEADS, usually serve as mere straight-men for the comic characters. But in Yeomen Phoebe, Fairfax, and Elsie all play three-dimensional, pivotal roles, especially in this production, because both comic principals are weak. Willis Emmons turns the razor-sharp, dominating role of Jack Point into a confusingly puckish, giggly supporting player. Some of the blame falls to director Paul R. O'Neill, who evidently has encouraged Emmons to read much of his dialogue in a jarring falsetto. In addition, Martha Weiner's Act One costume for Point bares too much resemblance to the costumes for the chorus of townspeople, diminishing Emmons's role further.

In several of his musical numbers, however, Emmons sheds his elfin aspect; in addition to his wonderful first duet with Elsie, he shows flashes of strong, satisfying comic talent in the "Creeping, Crawling" duet with Wilfred in Act Two. He also shines in the operetta's finale, bursting on the scene singing movingly the last refrain of "I Have a Song," and perishing. His actual death is regrettably melodramatic, but again, this is perhaps O'Neill's fault.

O'Neill's greatest weakness, though, comes in his own characterization of jailer Wilfred Shadbolt. The performance call unwarranted attention to itself from the moment the lights go up. The script of the operetta opens with Phoebe at the spinning wheel singing alone; this Yeomen begins with O'Neill clattering across the stage and mugging at the audience, all to no apparent purpose.

O'Neill also has the disconcerting habit of changing facial expression flamboyantly at every line he hears, particularly noticeable in O'Neill's many scenes with the exemplary Zabusky. The same heavyhandedness unhappily characterizes O'Neill's singing. His voice is rich and resonant but, like Sheldon's, somewhat stentorian under the circumstances.

To O'Neill's credit, though, this potentially unwieldy operetta moves along smoothly. The relatively large chorus of twelve, admirably prepared by musical director Richard S. Hoffman, plays its intricate crowd scenes fluidly and engagingly. The supporting cast, including Larry Indik, John Sneath, and Naomi Hirsch, is uniformly first-rate.

The orchestra, conducted the afternoon I attended by freshman wunderkind Stuart Malina, provided sturdy if uninspired accompaniment. Harriet D. Silbaugh's Tudor scenery has ginger-bread-house charm. And all in all, two misguided performances notwithstanding, the Harvard Gilbert and Sullivan Players give a classy operetta a yeomanly production.