Reporter Thembi Mutch spent seven weeks in Thailand and Cambodia, finding out what life is like for children trafficked into the region's thriving sex industry.
I arrived in Thailand on Friday morning, and by the evening my researcher and I were already scouring the bars of Bangkok, attempting to work out our game plan.
Many trafficked children have horrific stories to tell
We were in the region to find children who had been trafficked into sex work - those who are hidden away, often by armed pimps and traffickers in suburban bars and houses.
Prostitution is illegal in Thailand, although women and men are allowed to do bar work over the age of 18.
But in both Thailand and Cambodia, sex work is so lucrative for everyone involved that it is more blatant than almost anywhere else in the world.
It is not just tolerated, but unofficially, according to many non-governmental organisations (NGOs), it is actively encouraged by both the police and the government.
Posing as tourists
A recent memorandum of understanding between the countries in the Mekong region - including Thailand and Cambodia - has done much to stem child prostitution.
So too has more 10 years of aid work and advocacy by NGOs such as Save the Children and World Vision.
But despite this, resorts like the Thai beach town of Pattaya seem to be more like industrialised brothels than functioning towns.
The sex industry has also expanded to Cambodia, with many children employed as domestic workers, bricklayers, in fish processing plants, while at the same time dipping in and out of the best paid option, sex work.
Most of these children are not there voluntarily - they are trafficked.
Trafficking is helped along by the economic boom in South East Asia. The frantic rate of construction springing up in the region has brought more staff with a desire for young sex workers.
It is not an easy task to pose as "interested tourists" in these areas. We hung out on the streets at night, and got information of where children were working from local sex workers.
We recorded in blacked-out vehicles, changed hotels regularly, and I could never let the recording equipment be seen, or check my recordings, until I was safely inside the hotel.
Once, in Cambodia, we recorded traffickers making deals of children over coffee in a cafe in broad daylight.
The atmosphere was hostile, and the men were clearly on hard drugs, and drinking.
"Who are these people," I muttered to Ang, the ex-prostitute who was my fixer.
"They're Vietnamese and Cambodian government officials," she replied, and my heart sank.
We left immediately, aware that it costs $50 (£25) to hire a hit man in Cambodia.
We were followed almost continuously that day, and also on several others. Men on mopeds and motorbikes would pull up beside us as we raced through the capital Phnom Penh - me clutching Ang's waist, sitting pillion on her moped.
They would take a good, thorough look at my face, and then fall back behind us.
Tales of trafficking
As for the trafficked children, their stories defy words.
A 15-year-old girl in Cambodia said her parents had sold her to a man for her virginity. The man had drugged and raped her whilst she was unconscious.
After a week in the hotel room with this man, she was sold onto a brothel. There, she was gang-raped by 10 men posing as clients.
Girls can unwittingly find themselves put to work on the streets
She escaped, by hiding in a rubbish bin, but was then tricked into prostitution again, staying for three years. Eventually she escaped, and knocked on the door of some strangers, who cared for her.
She then made a two-day bus journey to Phnom Penh, where she arrived three months ago.
I also met a chatty, bright and wide-eyed nine-year-old, who, under a mango tree in the countryside, described how she had been kidnapped from the streets of the capital, locked in a house for a month, and made to watch pornography and drink water with human faeces in it.
The traffickers know what they are doing. She and the other girls were beaten regularly and never allowed out - all part of a systematic campaign to break down the children so they were too confused to do anything about it.
These children did not even know what sex or trafficking is, and whether they will ever "recover" from their ordeal is an ongoing debate.