Daniel Monte­negro plays Roméo and Rebecca Nathanson plays Juliette in the Castleton Festival’s “Roméo et Juliette.” (Tjark Lienke)

At the end of the prologue to Charles Gounod’s “Roméo et Juliette,” the strings play an excruciatingly ardent motif that is heard twice, once rising through an interval of a major sixth and then again ascending to a peak a half-step lower. This tiny difference inflects a mood of hope and desire to a darker, minor tonality, presaging the doom of the star-crossed lovers.

In a sense, the entire opera can be contained within the chromatic slippage of this little melodic cell. Gounod and his librettists weren’t particularly interested in Shakespeare’s theme of two families reconciled through the sacrifice of their children, but the composer compensated by constructing a nuanced sonic study of youth shadowed by death. Presentiments of sadness fleck the musical texture throughout almost every scene, and there is darker irony in the orchestration than one might expect from a composer so successful, so French and so effortlessly lyrical as Gounod.

Sadness also colors the opening of the seventh season of the Castleton Festival, the first without its founder, Lorin Maazel, who died last year. The first of the summer’s opera productions, a new staging of “Roméo et Juliette,” was preceded by Maazel’s widow, Dietlinde Turban Maazel, and his son, Leslie Maazel, welcoming the audience and asking for its financial assistance to perpetuate the festival and the legacy of its first leader and patron.

It’s a worthy investment — in the art form, its future practitioners and the local arts economy. The Castleton Festival engages young singers, some just launched on their careers, others still students, and pushes them to near-professional levels. This year’s “Roméo et Juliette” is as appealing as earlier Castleton productions, and it gathers force as it goes. No one will mistake the results for what one hears at the Metropolitan Opera, but this isn’t plodding work either. By the end of the show, technical deficiencies are forgotten, and a clear, powerful, emotional imprint takes precedence.

Which is to say, the young singers deliver on the promise of that sumptuous love theme, creating believable characters who engage our sympathies throughout the violence and misadventure that destroys their hopes of happiness and love. This year, the show belongs to the young man who played Roméo, Daniel Montenegro, a lyric tenor with a fine, well-supported voice who sang with great confidence and ease throughout Sunday’s matinee (the second of four performances). Montenegro has a natural sense of phrasing, an elegant line and a lovely, evenly produced pianissimo sound. Both vocally and physically, he created a youthful, vulnerable and decent Roméo, impetuous but not reckless in love. He can sing passionately but seems fundamentally a sensible singer, unwilling to push his voice beyond its limits. If his voice opens up a bit more and takes on the heroic ping that enables more mature singers to cut through thick textures, his incipient star power will be even brighter.

As Juliette, soprano Rebecca Nathanson grew in emotional force throughout the afternoon. Gounod bedevils poor Juliette with a light, skittering aria, “Je veux vivre,” delivered shortly after she arrives onstage in the first act. From this scintillating coloratura waltz, the role grows heavier and sits more solidly in the voice. Nathanson was happier as her instrument settled into this more dramatic sound, where its distinctive colors and textures were more audible. Nathanson and Montenegro make a compelling couple vocally, transcending individual limitations in the opera’s great love scenes in Acts II and IV and tapping a deep vein of despair and loss in the final act (where Gounod’s librettists, following perhaps in the tradition of the 18th-century English producer David Garrick, give the lovers an extended duet rather than Shakespeare’s lonely, sequential deaths).

There were strong performances throughout the supporting roles, from Erika Rodden as Juliette’s nurse, Gertrude; Tyler Simpson as Frère Laurent; and Kira Dills-DeSurra as Stéphano, the young page of Roméo. The Act III confrontation between Tybalt and Mercutio sparked genuine ferocity from tenor Leonardo Navarro, who sang Tybalt with a strong, focused, flinty sound, and baritone Paul LaRosa, who also delivered Mercutio’s Act I Ballad of Queen Mab with clean diction and impressive clarity.

The Castleton chorus is strong this year, despite a bit of messiness in the Act I ball music. And the orchestra, although it faltered briefly in the fugal episode of the overture, was well coached and unflagging under the baton of the young conductor Rafael Payare.

Dorothy Danner’s production, however, is too busy. Three large, moving set pieces are used for frequent and unnecessary reconfiguration of the single stage set piece; unnecessary background vignettes distract from the primary action and the singing; and there is an indulgent and rather fussy underscoring of symbolism. The effect of Tybalt’s bloody shirt, draped over a piece of furniture in Act IV, was more comic than intended. With young singers, as with melodrama, less is more.

It’s a pity not to see Maazel in the pit. The magic of Castleton has always been its small revelations from the singers and the orchestra. You might have heard something odd, intriguing or new and think: “I’ve never heard that before.” With Maazel in the pit, you could have confidence that such moments weren’t accidental.

But they’re still there, and it looks promising that they’ll keep coming. On Sunday it was a sudden sense of a light, almost comic orchestration when Frère Laurent explains the effects of the fateful sleeping potion that made the ears perk up. Gounod’s opera may sound more polished elsewhere, but it won’t often sound as authentic.

Roméo et Juliette

July 10 and 18 at the Castleton Festival. For more information, visit www.castletonfestival.org.