'Son of Perdition': FLDS Escapee Builds New Life Outside Warren Jeffs' Control

July 18, 2013— -- Deep in the desert, at a roadside memorial, Willy Steed paid his respects to his friends, fellow teens who died in a car crash after a beer party.

"I knew Vergie and Rachel and Jamieson…," Steed muttered.

In any other place, this would be a tragic footnote to an all too common aspect of teenage life. But Steed's hometown is anything but ordinary. The young people who died weren't merely partying -- they were violating a strict religious code.

Watch the full story on "20/20: I Escaped My Life" Friday at 10 ET

Colorado City, population 8,000, sits on the border between Utah and Arizona. The residents are members of the Fundamentalist Latter Day Saints (FLDS), a radical splinter group of the mainstream Mormon church exiled for their refusal to renounce plural marriage.

To live there is to turn back the clock a hundred years. No Internet, no television, no contact with the outside world. Every aspect of life -- what people wear, what they eat, even whom they marry -- is controlled by the man they call their prophet: Warren Jeffs.

PHOTOS: Inside Polygamy: Life in Warren Jeffs' FLDS Church

Jeffs is serving a life sentence for the sexual assault of children. Last fall, a yearlong "20/20" investigation revealed that Jeffs was still controlling his people's lives from behind prison walls, banning toys, bicycles and the eating of corn.

Boys and girls are forbidden from speaking to one another. Hence the secret desert parties.

VIDEO: FLDS Escapee Recalls Secret Desert Parties Where Teens Drink, Sexes Mingle

"There's a reason the young boys go out at night, and the young girls go to those parties," Steed said. "It's because they can drink, they can be themselves and they can put away all that stress."

FLDS church teaching holds that to attend these parties is to become a "son of perdition."

"Son of perdition means you are Satan's property, and that you will burn in hell when you leave this life for what you have done," Steed said.

Had he stayed here, Steed's name might be on the roadside memorial's cross alongside his friends'. But just weeks before the accident, Steed left.

"I realized I needed to get out and be who I was and not who everyone wanted me to be."

Steed escaped with the help of a group called Holding Out Help, a nonprofit for those leaving polygamist groups. The couple who took him in, Pam and Ron Jenson, was shocked to discover Steed couldn't read. Like most boys in the FLDS, he was pulled out of grade school to work.

The Jensons have helped Steed claim the childhood he lost: his first ride on a rollercoaster, his first birthday cake, and the brave new world of Facebook.

Steed has also met new friends who have opened doors to new possibilities. In June, a photographer, seeing potential in Steed as a model, brought him in for a photo shoot, completing the radical transformation he's undergone physically and emotionally.

"Someone saw me for who I was and singled me out and picked me because of that," Steed said. "All my life [I] never believed in myself. It was so easy for me to get lost in the crowd of family, but out here it's so easy to be seen in a crowd and not get lost."

Watch the full story on "20/20: I Escaped My Life" Friday at 10 ET