When Antonio Vivaldi’s opera La Verità in Cimento (Truth Put to the Test) premiered in 1720, the libretto revolved around a “Sultan” and his family. The recent Zurich production (Jan Philipp Gloger) gears it towards landed gentry in the modern era. A swap of two newborns starts the story: the rightful heir to a family fortune is switched with the baby of the father’s mistress, so that the bastard will one day attain wealth and position denied his mother.

A baby-swap isn’t a premise that sounds very promising, especially given that only the affluent Mamud and his mistress, Damira, know of the plan. But this is Baroque opera of the kind that brought enthusiastic crowds in great numbers to Venice in the early 18th century. Its intrigue unravels thirty years later when both boys fall in love with the same fickle woman, Rosane, who should wed the “supposed” heir, Melindo. As might be expected, guilt gets the better of Mamud; he is ready to confess and set the record straight.

For this − the very first run of La Vertità in Zurich − the staging (Ben Baur) was highly original. Vivaldi’s Eastern opulence was gone; it its place were the black-framed rooms of a stripped house façade. The audience followed action in the rooms as each one passed by like a slide ruler: an elegant entrance foyer between an up-scale dining room and the husband’s study, a peach-coloured bedroom, a cinderblock garage housing a handsome Porsche. The set’s soft-shaded interior showed lighting designer Franck Evin a true master of his craft.

The family’s “elegant casuals” (Karin Jud, costumes) showed the family ready for a day at the Club. Only the rightful heir son, Zelim (Anna Goryachova) varied from the norm, sporting a black Goth look and soft hooded cloak. Her character tried in vain to win back the love he’d once shared with Rosane (Julie Fuchs), even though the ambitious girl was determined to stay with Melindo, the son whom she believed would be coming into big money.

To Zelim’s great humiliation, she and Melindo flaunt their sexual delights in front of him; she even straddles his head with her knees as he plants kisses up and down her thighs. Vivaldi might not have portrayed the lovemaking quite as − convincingly. But Fuchs took liberties: her dress was revealing; her tremolos were delicate and feathery in their enticement; her chest voice showed her powerful in her convictions. “I found love with a future,” she sings to Zelim, “but if (the marriage) doesn’t work out, I promise to come back to you once more.” It was a line so painfully misguided that the audience let out a belly laugh.

The roles of the two half-brothers were also sung brilliantly. Countertenor Christophe Dumaux as Melindo accused Zelim of hidden aspirations in his aria “The serpent wriggles in the sands of the Nile, keeping itself well hidden…” and his shimmering technique brought generous applause. As Zelim, Goryachova was highly convincing as the jilted depressive; Zurich would do well to feature her stellar voice regularly.

The “tormented” husband, Mamud (Richard Croft), startled with his command of turbulent action alongside challenging vocal demands, while the maid Damira (Delphine Galou) was as convincing a witch as Miss Gulch in the “Wizard of Oz”. In her relentless scheming, she lent humorous relief, and sang well, barring modest trouble with her key when accompanied solely by the harpsichord. She also had a confrontation with Mamud that included a desperate striptease and strewing pillow feathers over his marriage bed. That was a hackneyed bit of drama, and could have been staged more subtly for better effect.

Yet, vital to the story, Damira tells Rustena of her husband’s baby-swap. As a betrayed wife and mother then trying in vain to save her dignity, Rustena (Wiebke Lehmkuhl) flashes digital photos of the two toddlers growing up together in her “bitterness and sorrow of suffering” aria. One of the most touching moments of the whole performance, it was a heart-wrenching lullaby. After all, Rustena was the true victim of Mamud’s contention: “Constancy that causes only sorrow vanishes into thin air when conquered by sweet love.”

Under the baton of Ottavio Dantone, the Orchestra La Scintilla played Vivaldi’s music with sterling precision, but also gave us less than the usual happy ending. Once the secret of identities is out, Melindo is stripped of the promise of inheritance, and he goes ballistic. In their tussle, Rosana accidentally fires a pistol shot that kills him, then turns the gun on herself. As was often done in Vivaldi’s time, however, the music was fitted to the drama the dramaturg (Claus Spahn) chose to use behind it. Indeed, the final aria accompaniment, borrowed from Vivaldi’s tragic score of L’incoronazione di Dario, was the ultimate tear-jerker; it pointed to how one man’s devious scheme had backfired entirely and taken his whole family down with him.