TEENS IN TROUBLE: CHRIS CUOMO REPORTS ON "20/20," FRIDAY, JANUARY 28 ON ABC

They started out like any kids, full of hope and dreams - but now they're homeless and in terrible danger of slipping between the cracks. These kids are not living under a bridge, but under the radar -- part of a new under-reported type of homelessness -- surfing from couch to couch, from the beds of friends to the beds of strangers. For over a year, Chris Cuomo and his team have chronicled the terrors and triumphs of four such teenagers, all surviving largely on their own. His report airs on "20/20," FRIDAY, JANUARY 28 (10:00-11:00 p.m., ET) on the ABC Television Network.

These children are part of a huge, largely unrecognized national problem. Among industrialized nations, the United States has the largest number of homeless women and children. Among those youth are nearly two million homeless teens. ABC News' "20/20" heads to the northwest to find this new generation of teens in trouble, an area of the country that has the highest percentage of homelessness, including a town where one third of its youth are without homes.

George, who ended up living in a tree for a few weeks in San Francisco's Golden Gate Park says: "I felt safer, because on the ground a lot of people could tamper with you. The only bad thing that could happen in a tree is if you fell out."

Dakota, who often slept at her friend's house since she says her mom left her in a parking lot when she was just 16, tells Cuomo: "I look at my friend and be like why just I couldn't be born in her family� she's got parents who, like, love her and support her in anything she'll do."

What kind of future do these kids have on the horizon? Tune in to find out.

"20/20" is anchored by Elizabeth Vargas and Chris Cuomo. David Sloan is executive producer.