CNN: Inside Cambodia's hidden child brothels

Women line outside a Phnom Penh karaoke bar where sex is sold. There are many such establishments on the road to Svay Pak, on the outskirts of the Cambodian capital.

Phnom Penh, Cambodia (CNN) -- Late one night, after dark, we met up with Don Brewster -- head of Agape International Missions, an NGO fighting child prostitution -- to go behind the scenes at Cambodia's KTVs: karaoke clubs that are fronts for brothels.

I threw on some jeans and tried to look like a tourist who was up for a kinky kind of tour, with my ersatz "boyfriend"-- our cameraman, Scott....

Don drove us first to an out of the way small side street, where there were tiny KTVs operating out in the open like cheap brothels. Girls sat on plastic chairs lining the entrance, all painted up and wearing short skirts, high heels and fake smiles. We walked past a few, stopping to talk for a little while. The girls would stand up, becoming energized and engaged. We crossed the street and approached another one, as if we were sampling the wares at each one.

We walk into a KTV; Scott and Don lead the way into the karaoke rooms. I become less nervous as we walk to the back where an overweight young woman frantically sweeps the kitchen floor, and we are pointed up some cement and metal stairs. We pass hallways full of closed doors, in which I can only imagine the sex acts occur.

We are brought into a low ceilinged, dank room with some disgusting couches and a video screen on one wall. I am overwhelmed with the saturated smell of air freshener that apparently has gone off like an insect fogger in this room -- to cover what odor, who knows. I nearly gag and we beat a quick path out of there. We hop back into the car and head off.

Next stop: a famous 5-storied fortress of a KTV with armed guards outside. Don says if we take the elevator up from the basement, we can skip the bar and go straight to the "massage" floor.

On the fifth floor we are immediately led to a giant windowed "fishbowl" where at least 20 girls sit on bleacher to be observed and picked. Scott walks in front of the pane; they respond to his macho energy, rising and preening.

I have my iPhone in hand and itching to take a picture when suddenly things go horribly sideways: A white-clad girl in the bowl suddenly jumps up and starts screaming "She take a picture!!" She runs into the lobby and a grim-faced Mama-san bustles up to us. The girl crowds us and accuses me; more people start to gather. My friends advise me to erase the picture -- but I haven't taken any! I try and stand my ground and keep saying, "I didn't take a picture." But I am becoming very nervous and the situation is getting ugly.

We hustle back onto the elevator. We were lucky to get out of there without running into the security guys, because there could have been real trouble. But their behavior absolutely cemented the fact that something illegal, beyond legal-aged prostitution is going on there. They were acting like they had far too much to lose.

We head to another KTV, this one still upscale but less fortress-like than the last. Paintings of the cosmos line the ceiling in the lobby. We were ushered in and led us upstairs to karaoke room where hostesses in satin, beaded formal dresses greet us. The large and comfortable room had a giant screen on one wall and couches lining the other three walls. Colored lights pulse and change on the walls.

An older woman walked in five girls dressed in fairly classy though sexy business suits, for us to take our pick of whom we would like to stay with us. Scott, fully playing the part, roars out in his New Zealand accent, "You have anything younger, fresher?!" The girls scurry out in a hurry.

Then more girls enter. These definitely seem younger. They are also more provocatively dressed; they are wearing very short little black dresses. Don picks one, and so does Scott and the two join us; the karaoke starts in earnest. I must sing with gusto to justify my presence, otherwise what is this white lady doing here?

We sit there and begin to get their life stories. The young girl sitting next to me, the one Scott chose, is extremely pretty. It is impossible to tell how old she is -- she claims to be 21, I would believe it if she was 14. She says she doesn't come from Phnom Penh, and she is working here because her family is very poor and needs the money. Her family doesn't know what kind of work she is doing, she said. If they find out, they will be angry with her. She has a very pretty smile, but there are moments when I watch her where the smile disappears, and she looks very sad.

She chooses to sing a song from the Karaoke catalog, a popular dance hit in Khmer, which has a video of a singer performing in front of what looks to be an American style high school dance, again like a prom. I am told the song is called "Only One Virginity" (!) and it talks about how a girl is like a flower, and only has the one time where she has most value.

Our young acquaintance sings her heart out, very intently performing if not always tunefully. Afterwards she tells me that she very specifically picked this one out, and that she wishes that she will meet a man that will go to her parents and ask for her hand, respect her. I try to get her to talk about what men expect from her here, but it doesn't go very far.

I see that Don has been very busy with the girl he invited to stay, showing her a video on his iPhone in which a girl from his center talks about how she was able to leave a KTV and now has a job that she is excited about and is much happier. She was very intrigued by the video and she gave him her cellphone number so the girl from the video could call her and follow up.

I passed his iPhone to our young companion. Thankfully, the hostesses did not seem to mind or care that we were doing this; the whole room was on security cameras poised in the corners but no one came in and stopped us. She watched and listened to the video very intently. Afterwards she said she liked it.

"I know it is hard to trust us, strangers," I told her. "But I am a mom (and I showed her pictures of my four happy children and me hugging my two daughters) and I wouldn't want my kids in a situation like this."

She didn't give her number, but we told her it was okay, Don's outreach person would call her friend and we gave her Don's card. I impressed on her that this was opportunity knocking on her door, and she should answer it: this was her chance for a happier life.

We hugged goodbye, and went back to the cars. I had no idea that I was going to be involved in trying to recruit girls to leave the KTV life and receive the services of Don's NGO. What a night.