Rain mars Mozart in the ruins by Mill City Summer Opera

Strange things can happen when you go to an outdoor opera performance. Halfway through Act One of Mozart's "Così fan Tutte" at the Mill City Museum ruins in downtown Minneapolis on Sunday evening, a public address announcement cut into the music and called all the actors and musicians offstage.

A few spots of rain threatened, but a shower failed to develop. Twenty minutes later the show restarted, without the orchestra, only to shut down again when some real rain fell.

In the hourlong interval that followed, the singers moved indoors to the museum lobby, where they skipped the first-act finale and performed Act Two with a selection of props and a keyboard.

It was a hugely frustrating evening for the Mill City Summer Opera singers, who coped gallantly with the constant interruptions. The 40 minutes of fully staged action in Act One had developed an intriguing momentum before the elements turned murky.

This "Così" was the inaugural production of Mill City Summer Opera's new artistic director, Crystal Manich, who updated the opera from the 18th century to 1940s Italy.

In her reframing, the young blades Ferrando and Guglielmo are recently discharged soldiers returning to a town where bomb damage is evident and the inhabitants exude a zoned-out, post-traumatic languor.

Their sweethearts Fiordiligi and Dorabella have an edgy appetite for the amorous excitements denied them during war, and are cruelly disappointed when their fiancés are apparently recalled to front-line duty. It's all a grisly ruse, designed by Don Alfonso and the boys to test the girls' fidelity in a thoughtlessly laid wager.

Manich turns Don Alfonso into a disheveled ex-general with a drinking habit, who concocts the grubby scheme more out of boredom than any sense of malice. Baritone Andrew Wilkowske made an unusually sympathetic impression as Alfonso, somehow managing to suggest that for all his cynical maneuvering of the callow youthful lovers he is ultimately doing them a favor. He sang splendidly, and managed to survive the sweltering humidity in a distinctly unseasonal military uniform.

Soprano Karin Wolverton and mezzo-soprano Sarah Larsen made a strong impression as Fiordiligi and Dorabella, deftly balancing the occasional frivolity of the characters with their deeper emotional complexities.

Manich's astute take on "Così's" characters extended to Ferrando (Javier Abreu) and Guglielmo (Sidney Outlaw), who emerged as desperately immature and short of life experience, not deliberately cruel and unlikable.

Before the orchestra packed up, conductor Brian DeMaris drew some warmly expressive playing at relaxed tempos, which gave welcome scope for the subtle nuancing of Mozart's scoring to register.

"Così fan Tutte" is the last show Mill City Summer Opera will be staging at Mill City Museum before crossing town to Paikka, a renovated industrial space in St. Paul's Midway district, for its 2020 season.

There, a roof is promised, with air conditioning for hot weather. Sunday evening's doughty cast of performers could have done with both, as could the patient audience.

Terry Blain is a freelance classical music critic for the Star Tribune. Reach him at artsblain@gmail.com.