As a result, the after-hours scene here caters mainly to the well-off.
"Compared to Jakarta's sex workers, whose whole lives are a gamble, the city's high-rollers have it easy," Emka writes. "In illegal casinos throughout Jakarta, big-time gamblers play the tables and play the women who work there."
While nightlife in Jakarta is unashamedly oriented towards men — Emka did touch on how some women choose their profession for the money — there has been an increase in services specially tailored for women.
"In a great show of sexual equality, Jakarta's monied ladies throw a wild poolside party where the sex workers are men," Emka writes.
But at most venues, including this one, women who don't work there are strictly forbidden upstairs.
As they say in Indonesia, "tidak apa-apa," or "no worries" — at least, not tonight.
The elevator doors open, and upstairs there's a bar, saunas, lounge chairs and several shallow pools. Without the knowledge of what goes on there, it looks like a resort, only indoors, with trees.
A number of other places like this have opened up in Jakarta. "Add a second girl and you have a Double-Service Sauna Special, add a third and you have the ultimate in uplifting VIP sauna treatments: the Triple-Service VIP Sauna Special," Emka writes.
It is past three in the morning and Emka stops at a local warung, or food stall, before heading home. He is served rice, chicken and vegetables where even the vendors know him by name.
Emka plans to expand his undercover knowledge to other hot-spot cities around the region, but Jakarta is still number one, he said.
"When people come here they are surprised that Jakarta has this, and Jakarta has that," he says. "But they get over it quickly, and want to try."