KATHMANDU, Nepal (CNN) -- We went from store to store in Kathmandu, Nepal, talking with shopkeepers and trying to find one of the country's thousands of "kamlaris" or female-child bonded laborers.
Kamlaris are part of a deep-rooted tradition in Nepal that remains quite strong today. "One lives in that house," we kept hearing, or "I've seen one over there."
With help from several aid organizations, including the Nepalese Youth Opportunity Foundation, we finally met a kamlari. Her name was Subita.
Subita didn't know her own age, though she looked quite young, most likely about 12 years old. She scrubs dishes, watches the children, mops and sweeps the floors for a family far away from her own, she said. She hasn't spoken with her own family in more than a year. (Watch how a girl lives after being sold as a laborer -- 3:28)
Subita is just one of an estimated 20,000 young girls from the Dang and Deukhari valleys who are sold by their own families to work as bonded laborers in one-year contracts, according to aid organizations. Often the contract is renewed year after year. The kamlari practice is centered in those two valleys.
It is illegal to employ someone under the age of 14 in Nepal. According to Nepalese law, the onus of verifying a child's age is placed on the employer.
The indentured child usually does not see any of the money herself, but the families earn roughly $50 per year for each kamlari, according to aid organizations. A middleman takes the girl away and finds work for her, which is often in a distant city. The parents and children often don't know how to find one another.
We traveled to the Dang district in western Nepal to try to understand why these families sell their children. There are five districts in this region where an indigenous group of people known as Tharus have sold their daughters off as workers to other families for generations.
We met Subita's father, Sundar, in a dried-up rice paddy as he cut blades of grass. Since he doesn't own any land of his own, he works on government land and hopes he won't be kicked off it. Sundar told us that his life is very difficult and that he was sad to send his three daughters away to be kamlaris.
Subita and her two sisters were all sold by their parents. Each of them fetched a different sum for the family -- between $25 to $40. Aid groups said part of the alleged benefit to the family is that the family doesn't have to pay to feed, keep, and clothe their own daughters. Middlemen also often promise that the girls will go to school. Aid groups like the Nepalese Youth Opportunity Foundation said that promise is seldom kept.
Others in the village have also sent their daughters away. It is a tradition that aid groups are working to break. Several organizations work with kamlaris and their families, including Society Welfare Action Nepal. "The girls only earn a few thousand rupees," said SWAN's Krishna Chaudhary. "So what we are trying to do is replace it with a kid of a goat, so they can go out and they can sell the meat, and they can recoup that investment from the animals."
Aid groups say that just $100 per year per child is enough of an incentive to the girls and their families to break this cycle. Som Paneru, executive director of the Nepalese Youth Opportunity Foundation, which funds local organizations working with these girls, said becoming a kamlari is often a life sentence for these girls.
"Generally, the girls work as kamlaris for some 10 years in their lives. ... After the girls become 16, 17, 18 years of age, they become empowered, and they are able to say 'no' to the order of the employers. Once the girl is 17 or 18 years old, they are sent back to the families, or they go somewhere else for whatever occupation they can take to survive. It could be prostitution. It could be, you know, dancing in a restaurant," Paneru said.
For now, Subita works in a home in Kathmandu, most likely unaware of the struggle to stop this practice that swirls around her. Subita's mother told us that she didn't want to send her daughter off to work as a kamlari.
"We are poor people. ... What are we to do?" she said.