Shanta Chaudhary was eight years old when her parents sold her into effective slavery for $75, sending her to scrub, cook and sweep for 19 hours a day at the house of a stranger in southwestern Nepal.Now a strident rights campaigner, politician and one of the country's most influential women, she weeps as she recalls 18 years spent as a "kamlari", rising at 4:00 am, receiving regular beatings and witnessing rape and abuse.
"I remember the torture. I had to carry weights much heavier than me even when I was sick. And I couldn't see my parents and I could never experience a mother's love," she said.
"Even my married years were spent in someone else's house. When I think about my past my heart seems to burst. Many kamlaris were even raped and I have seen it myself."
The kamlari system is a form of indentured servitude that persists 90 years after the official abolition of slavery on the plains of southwestern Nepal, a world away from the temples of Kathmandu and the Himalayan peaks which attract tourists from across the world.
For generations, ethnic Tharu girls as young as six have been handed over to higher caste landlords and brokers, committed to years of menial labour and subjected to a wide range of cruelties.
"Child labourers can't get to sleep at night, they can't play, their hands are rough from work and they have no love. It's a really scary situation for them," Chaudhary told a recent UNICEF conference to mark World Day Against Child Labour.
A century ago the Tharu, said to be descendants of Buddha, owned their farms and lived in relative isolation, enjoying a natural resistance to malaria common to the Terai plains that the higher castes lacked.
But when the disease was eradicated in 1960, the illiterate tribes were displaced by higher-caste hordes streaming down from the hills and became serfs in their own land.
Now, destitute families saddled by debt lease their daughters for as little as $30 a year, the equivalent of around 10 percent of their annual income.
The Nepalese Youth Opportunity Foundation says it has encountered kamlaris working for high-ranking Communist Party leaders, lawyers, journalists and even the police.
Chaudhary was brought up in Dang district, a dry, subsistence-farming region where thatch-roofed mud huts have no electricity and feeding the family is a daily struggle.
Her parents, who had nine children, were landless and couldn't find work, and so agreed to take 6,600 rupees ($75) a year from a high-caste landlord for Chaudhary.
She was set to work, beginning household chores at 4:00 am and often finishing as late as 11:00 pm, surviving on a diet of wild corn collected from a nearby forest and frequently beaten.
"I had to work so much my hands were never dry. My entire childhood, my adolescence, even my motherhood, were all spent as a kamlari," she said.
But Chaudhary, now a composed 32-year-old with a winning smile that masks the torment of her childhood years, was able to break out of her servitude and is helping other trapped girls.
She was freed by a 2006 Supreme Court ruling outlawing the kamlari system, and led a land rights movement that reached Kathmandu, bringing her to the notice of the Unified Marxist Leninist party.
In Nepal's 2008 general election, Chaudhary was given one of the party's parliamentary seats allocated under a proportional representation system.
Initially derided by colleagues for being illiterate, Chaudhary learned to read and write and was put in charge of the influential parliamentary committee on natural resources.
"Even in the homes of government officials and people working in human rights fields there is child labour," Chaudhary said.
"And as long as we don't raid those homes this problem is not going to be solved."
A decade ago, an estimated 14,000 girls were locked in the kamlari system, but thanks to activists like Chaudhary the tide is turning and charity groups have rescued thousands.
Nevertheless, the US-based Nepal Youth Foundation says around 1,000 Tharu girls remain indentured, most in remote villages or with powerful families in the capital.
"These children face severe violations of their rights. It is children's right to be children, to be able to grow, study, have fun, in a protective environment," said Will Parks, UNICEF's deputy representative in Nepal.
The International Labor Organization is working with the Nepal government to implement a "master plan" to eliminate the worst forms of child labour by 2016.
Gauri Pradhan, of the National Human Rights Commission, believes the impoverished country has made some progress but is still a long way from eliminating the problem.
"The numbers of working children under the age of 14 in the country has reduced dramatically but at the same time the number of children aged 15 to 17 working in the worst forms of child labour has gone up," he said.
"The challenge is to provide educational opportunities to the working children deprived from going to school, and help build up a more skilled and literate young labour force for the future."