"Buy yourself something nice."

Such innocuous words are now being sung - repeatedly, with significant implications - in The Shops, an opera about obsessive acquisition, being performed by Center City Opera in the belly of the beast: the subterranean Market & Shops at the Comcast Center.

Nobody is saying this food-court venue - where performances take place at 8:30 p.m. Friday and Saturday and 5 p.m. Sunday - is an improvement over the Academy of Music or the Kimmel Center. The point is creating an alternative to large-theater opera that's steeped in long-beloved classics. There's the added novelty of staging an opera in its real-life environment.

"In the arts, we've lost the idea of surprise," says Albert Innaurato, who stage-directs the production. "The power of the arts is not knowing what you're going to get."

The fast-paced, hour-long piece by composer Edward Rushton and librettist Dagny Gioulami premiered to healthy acclaim in 2007 in Birmingham, England, and was discovered by Center City Opera's general director, Andrew Kurtz, as part of the company's ongoing mandate to cultivate and perform new work.

In the spirit of such modern classics as Postcard From Morocco and Six Characters in Search of an Author, The Shops takes a dreamlike approach to extremes of emptiness and entitlement in modern consumerist culture, with six characters shopping and shoplifting their way through 26 scenes depicting shops, self-help groups, and seedier environs for unsuccessful kleptomaniacs.

"It's about needing things and wanting things to fulfill yourself," says Kurtz. "The main character, Christoph . . . finds love through acquisition. Even his parents don't love him, because they're collectors."

With singers making their entrances from a giant shopping bag and generally coping with an improvised stage, the cast of necessity is devoid of divas, mostly singers in their mid-20s with backgrounds in conventional theater.

Young women will parade around with signs - wrestling-match style - to delineate the quick-shifting scene changes, a creative reaction to performing opera in a place lacking the lights and scenery that normally would fulfill that function.

The relatively low ceiling poses fewer acoustic challenges than typical cavernous malls, and the opera's clarinet-dominated instrumental ensemble won't have the projection problem of string instruments. With tickets ranging from $20 to $39, the message is: "You don't have to be so special or so elect or so rich to have this completely unusual experience," says Innaurato.

Not that mall opera is so unusual in Philadelphia. In April, Opera Company of Philadelphia staged a flash-mob version of the Brindisi from La Traviata at the Reading Terminal Market and, in October, coordinated a mass "Hallelujah Chorus" for surprised shoppers at Macy's. Center City Opera performed Elixir of Love at the Italian Market in September. Part of the current project at the Comcast Center includes lunchtime aria concerts sung in front of DiBruno Bros. in the concourse.

"I wish they did it all the time," said Rudy Wojtkwoski, an on-break SEPTA employee, who found himself with a ringside seat - and admitted to enjoying it much more than soap opera. Some listened intently. Some kept heads buried in laptop computers.

"It forces us to focus," said soprano Monica Pasquini, 25, who inserted extra high notes so her Tales of Hoffmann aria could be better heard.

Less entertaining are the public rehearsals, also in front of DiBruno Bros. Failure is part of that process. And this time, singers are faced with the prospect of failing in public. "And we do," said Pasquini.

It's back-to-basics theater, which Innaurato practiced in his Philadelphia younger years (before writing his Broadway hit Gemini), when he ran the Demitasse Opera Company that performed Mozart's Cosi fan tutte even more exposed to the elements - out of the back of a truck.

At least the late-afternoon foot traffic is usually people too preoccupied with catching a train at Suburban Station to notice how rehearsals are going. Also, the company has the support of the building's management - in contrast to the false starts Center City Opera had with other venues that fell through.

"We're willing to make the commitment," said Joe Wolf, retail director of the Comcast Center. "The market closes at 8 p.m.," a half hour before The Shops is to be performed. "So let's make it available."

"The Shops"