Karen Brooks has decided that you don’t mess with success. Brooks helped found Mill City Opera three years ago and then watched as the small, summer company sold out short runs of “Pagliacci” and “The Barber of Seville.”

The company’s third year opens this weekend with “Tosca” playing under the twilight sky of the Mill City Ruins along the Mississippi riverfront, and again it will be tough to get a ticket (rush seats are available, otherwise all shows are sold out). A performance has been added and two special stagings of a show called “Guns and Rosenkavalier” have been added as a spritzy tonic to the season.

Brooks, though, squelches any suggestion that Mill City might have a bigger appetite.

“There is already a major opera company in town [Minnesota Opera], and there’s no reason for us to do anything huge,” she said. “We like to think we’re bringing new people to opera because of the format.”

Mill City has fashioned this success out of several elements: Minnesotans love to be outside in the summer, and the Mill City courtyard allows them to feel the heat at the same time they are enjoying opera; the ruins become a dramatic backdrop that helps define the aesthetic look; the confines of the 350-seat space forces an intimacy that draws an audience closer.

To extend the season would work against the economics of opera, where additional performances trigger higher costs. Tax returns from 2013 show ticket revenue of about $121,000, about 24 percent of total revenue of $498,000. Contributions and other income allowed the organization to shave off a surplus of $13,000 on expenses.

More important to Brooks is the nature of an event that she describes as “artisanal, or a boutique.”

“Half the audience is under 50. They enjoy the casual experience where you can eat and drink in your seats,” she said. “We need to stick to this model.”

Jealousy, love, tragedy

Puccini’s “Tosca” figured in the genesis of Mill City. Brooks said they used the image of the famed soprano, Tosca, plummeting from one of the parapets of the Mill City ruins as a selling point — a dramatic image that would be uniquely available in this space.

But the company needed to mature with the first two seasons, she said, before taking on the high drama of a diva whose love for a painter is challenged by an obsessive and evil chief of police, Scarpia.

David Lefkowich, as he has the previous two seasons, returns to direct the production. The real-life married couple of Jill and Jake Gardner sing the central roles of Tosca and Scarpia. In this production, Jill Gardner, as Tosca, will plunge from a 15-foot parapet on the ruins, as part of the dramatic denouement.

Actually, she said, it’s 12 to 15 feet. And because of a pole-vaulter landing mat, the actual fall is closer to 8 to 10 feet. That’s still a heckuva stunt.

“I love that moment in the opera,” Jill Gardner said. “It draws on the daredevil in me.”

Jill and Jake don’t often get the chance to perform on the same bill. She’s off to Idaho after Mill City and he’s headed to Virginia, for example. But they get to trade emotional daggers in the Minnesota production. Their relationship allows a comfort once the venom rises.

“I know Jake in a way that is not like the way other performers do,” said Jill. “You can give yourself over to the dramatic, knowing that the other person is playing the character. We love deeply, and not that I would ever kill him, but you’re allowed to go to the fullest extent because this person is your partner.”

Jake Gardner, comforted to hear that his wife doesn’t want to kill him, said Scarpia is “arguably one of the most beautifully crafted roles for any voice type.” Puccini gave the character a clear identity of evil, though the actor needs to bring the human manifestation of that evil to bear.

“He’s easy to play because he’s so well delineated,” Jake said. “But you can’t play evil. You have to put him in a human form that moves the audience.”

Something really different

Brooks and her company have been fortunate in Mill City’s first two seasons. In 10 performances, they have experienced no rainouts. They have a plan, of course, to move a production inside, but no one wants to spoil the signature element of this opera.

“I think we’ll be fine, but our fingers are crossed,” Brooks said.

The company introduces a new element this year, a two-night presentation of “Guns and Rosenkavalier,” a mash-up of opera and rock ’n’ roll headed by Andrew Wilkowske, a singer with Minnesota Opera.

“Andy has worked on this at other places — Milwaukee, Glimmerglass — and it’s been a big hit,” Brooks said. “We’re big Andy fans.”

If you’re still looking for tickets to the season, this show offers the best shot. It’s not sold out.

“There’s a wonderful energy here,” said Jill Gardner. “It’s not just about trying to survive. It’s nice to be part of something that is fresh and new.”