Women in short skirts and men with gelled hair bump and grind on a dance floor as a disc jockey pumps up the volume. The air is thick with illicit smoke and shots of hard liquor are being passed around. Couples kiss in a lounge.
This is not Saturday night at a club in New York, London or Hong Kong. It is the secret side of Pakistan.
Created out of Muslim-majority areas in colonial India 65 years ago, the country for decades portrayed itself as a progressive Islamic nation. Starting in the 1980s, however, it has been drifting towards a more conservative interpretation of Islam.
Yet the country remains home to a large, wealthy and Westernised elite that, in private, lives very differently.
Every weekend, fashion designers, photographers, medical students and businessmen gather at dozens of parties in Islamabad, Karachi and Lahore to push social boundaries in discreet surroundings that would enrage hardliners.
"This is just epic," said Numair Shahzada, at a party in a farmhouse outside Islamabad.
To avoid prying eyes, the parties are held in such venues in the outskirts of Islamabad and other cities, or in affluent neighbourhoods behind high walls. Organisers charge around US$60 for entry, an amount most Pakistanis earn in a month.
Although alcohol is prohibited in the country, many have brought their own liquor. Whisky is carried in paper bags and vodka is disguised in water bottles arranged along the dance floor.
The party-goers form a tiny minority of the country's 180 million people, but overall, Pakistan is not repressive. Women can drive, are enrolled in universities and have played prominent roles in politics. Unmarried men and women can interact without risking the wrath of religious police.
But a conservative form of Islam is chipping away at this tolerance.
A few hours' drive from Islamabad's party circuit, parts of remote tribal regions have fallen under the sway of hardline Taliban militants, who dream of toppling the US-backed government and creating a society where revellers will face flogging, or worse.
"Men and women who dance together are damned by God. Whenever we see such displays of vulgarity we will definitely make them a target," said a senior Taliban commander.
News reports have said a tribal council in a village near the Afghanistan border ordered four women killed earlier this year for clapping and singing as men danced at a wedding. The Supreme Court has ordered an investigation, but there have been no further details.
"You can either be God-fearing or you can party," said Rafia, a regular on the party scene, while she smoked a marijuana joint.
Pakistani rapper Adil Omar, who attends weekend parties, pokes fun at the Taliban and rising conservatism in his songs. But he never goes too far.
"I am careful not to give any opinions regarding religion," he said. "I don't want some crazy person chopping off my head."