Wei Zebo normally can't wait to go home for Chinese New Year at the end of January. Only this year he doesn't dare.
Like 60 of his construction worker colleagues, he is locked in a dispute with his former employer over back pay worth some 100,000 yuan (US$12,390).
"I haven't plucked up the courage to tell my family. I can't go back without the money," said Wei, 35, sitting huddled in a tiny freezing room lit by a single, dim, bare bulb in a gritty, working class area of Beijing.
"Look - I'm all packed," said the native of the northern province of Hebei, gesturing to a small pile of cheap-looking hold-alls sitting atop a bed covered with a filthy quilt. "I just need to be paid."
Wei's case is typical of a larger problem in China, where millions of migrant workers from poor rural areas have flocked to cities to find work, hoping to enjoy some of the fruits of an economy clocking near double-digit growth.
Working often for as little as US$2 a day or less, they have helped turn China into the workshop of the world and the sixth largest economy on the planet.
Yet in past years, some of the estimated 100 million farmers who have moved to booming cities to find work have been unable to go home because they have not been paid in months.
In 2004, 20 billion yuan owed to migrants went unpaid, according to the official Xinhua news agency.
The government has vowed to crack down on errant bosses. It has ordered companies and contractors to pay back wages to migrant workers before the Lunar New Year in late January when most Chinese try to return home for the holidays.
But with many of these laborers working without formal contracts, they have little recourse to the law in case of disputes.
"We've complained to the labor affairs people, but they said we had no rights as we were working illegally," said Gao Xingxin, 36, from the southern province of Hunan. "It's not fair. We'd signed an agreement with the boss."
A series of suicides and violent attacks committed by desperate unpaid migrants have drawn attention to their plight.
Some have thrown themselves from buildings they were helping to build.
In September, a gang of migrant workers, apparently driven to despair over unpaid wages, attacked their boss and his wife, broke their limbs with iron bars and tried to hack them off with cleavers.
And in May, a laborer insulted by managers when he tried to claim unpaid wages went on the rampage and killed four people.
All this worries a government obsessed with stability and worried any protests may spin out of control and challenge the Communist Party's authority.
"I understand the frustration of migrant workers who steal and do other bad things," said Sichuan province native Tan Jinzhe. "We just want to be paid for our work, like everybody else."
They called a government hotline set up especially to help workers who have not been paid, but the volunteer lawyer assigned to help them has only shown up once, and they are not optimistic he can help.
They have already been thrown out of their dormitory at the work site, and about 10 of them now live squashed together in a single unheated room barely larger than a pool table, off a rubbish-strewn lane in the shadows of posh new apartment blocks.
The group is keen to stress that they are good, patriotic Chinese, though, and say they do not oppose the government.
"We're not saying the government is bad," said Gao Changming. "This sort of thing happens in America, even in England, doesn't it?"
But they do not want the address of their current place of residence revealed and say they are scared of the police.
"They terrify us," said Wei. "They are all in cahoots with our former boss."
And despite the sweat and blood they and millions of others have put into giving many formerly bleak Chinese cities shiny, futuristic new skylines, they say they are not appreciated.
"We do the dirtiest, hardest work, and everyone looks down on us," said Gao.
"We're only trying to 'serve the people,'" he said with an ironic laugh, referring to former Communist Party Chairman Mao Zedong's famous exhortation.