The giant cube beckons. But it will not yield. At least not until Friday.

Standing guard at Fifth Avenue and 58th Street is a massive cube covered in matte black construction material. Underneath is reportedly a 32-foot glass cube that will soon become the entrance to Apple’s new mega-store.

Apple has posted a countdown to the unveiling on its Web site, but the company is refusing to say much more. At the construction site yesterday, individuals wearing identification cards bearing the Apple logo would not divulge the cube’s purpose. They were mum on its designer. (There’s buzz that it is CEO Steve Jobs.) They even kept tight-lipped on the products and services that would be offered in the more than 20,000-square-foot basement-level shop at General Motors plaza. Calls to Apple’s corporate offices in Cupertino, Calif., were not returned.

Apple employees yesterday filtered in an out of what appeared to be an alternate store entrance on the southwest side of the G.M. building. Meanwhile, a handful of Apple security guards are charged with keeping away curious onlookers and would-be photographers.

Renderings of the cube surfaced online, but not at any official Apple Web site. The project’s developer has renderings of the plaza featuring a giant question mark over the glass square. The cube is said have cost $9 million to erect and bears more than a passing resemblance to I.M. Pei’s controversial glass pyramid entrance to Paris’s Louvre Museum that opened in 1989.

With the opening of the store just days away, some New Yorkers are keenly anticipating the unveiling. For months, the massive structure has been shrouded in what appears to be a black plastic coating. Theodore Crispino, a paralegal for the law firm Weil, Gotshal & Manges, which has offices in the G.M. building, said that he and his colleagues have waited for months to see what was beneath the dark veil.

Mr. Crispino, a 29-year-old who owns an Apple laptop and two iPods, said it would take willpower to keep from purchasing the newest Apple gadgets, and acknowledged that he might occasionally give into temptation. “It going to be a whole lot easier than going to the downtown,” said the Upper West Side resident. “This means I’ll probably be upgrading my iPod sooner,” he said.

The new store is located about three miles north of Apple’s flagship store, which opened about four years ago on Prince Street in Soho. Pausing yesterday in front of the covered-up cube, a tourist from Kfar Saba, Israel, Oren Danieli, 30, guessed that the construction workers working nearby were putting up a monument. “When you build a computer store, that’s not what it looks like,” he said.

An 18-year-old tourist from San Antonio, Brandon Bradley, was surprised to hear that the cube would be home to a high-tech retailer. “I would have never guessed that’s what it was,” he said, noting that the Apple Store in his hometown had a far more modest entrance. Mr. Bradley added that he purchased an Apple iPod just last week and loaded songs by country crooners George Strait and Brad Paisley.

As he walked out the Apple’s SoHo store yesterday, a 33-year-old Harlem resident, Dino Deas, said the new store would be convenient for him. “I will definitely be going there,” Mr. Deas said. “I’d rather not travel all this way if I’m having a problem with my iPod.”

Judging by the foot traffic in the downtown location, he said he’s confident that the Manhattan market would support two Apple mega-stores – and maybe more. And with the new store in the shadow of the flagship FAO Schwarz, the new Apple outlet is set to become an uptown adult playground.