Four years ago, Sam Sally left her hometown in Elkhart for a vacation in Turkey. During the trip, Sally claims her husband duped her and her children into joining ISIS in Syria.

Now out of Raqqa and in Syrian Kurdish custody, Sally must explain how her husband died fighting for ISIS and prove her innocence to U.S. authorities if she ever hopes to return home with her four children.

Sally told CNN'S Nick Paton Walsh that she had no choice and recounted how her husband, Moussa, became abusive, bought teenage Yazidi sex slaves and made her 10-year-old son appear in one of ISIS's propaganda videos.

The story of how an Indiana family went from a mundane life of sports cars and a delivery business to joining ISIS and seeing their son as the face of ISIS propaganda against America is one of mystery, compassion and savagery that stretches belief.

"All I saw was a bunch of drug-using thugs that came from their countries who had no place," Sally says.

Thirty-two-year-old Sam Sally, 10-year-old Matthew, and 5-year-old Sarah, as well as Sally's youngest two live in the so-called ISIS caliphate and are now in Syrian custody.

Whether they go home or not depends, in part, on how well Sally explains her innocence in the four-year ordeal behind them.

Her story begins with a vacation to Turkey. That led to a border town, where she says she was duped to crossing into ISIS's world.

"There will be people who simply don't believe you," CNN Senior International Correspondent Nick Paton Walsh told Sally .

"They can think whatever they want to believe, but they've never been put in a situation to make a decision like that," Sally said.

At the ISIS border crossing, she says she faced an impossible choice: her husband grabbed little Sarah, while she had Matthew.

"The position I was in was to stay there with my son or watch my daughter leave with my husband, and I had to make a decision," Sally explains. "I thought -- like I said -- we could just walk across the border and we could come back again."

She chose to keep the family together. But it's hard to believe Sally didn't ever realize what she was getting into. It was also when the gentle comforts of her marriage ended, and her husband, Moussa -- who never even seemed devout in America -- became an abusive monster.

"Before, he used to spoil me -- 'I love you.' I mean, we were very much in love," Sally says. "The romance never left. As soon as we came here it was completely different. Everything was completely different. I was a dog. I didn't have any choice. It was extremely violent."

Moussa traveled a lot to fight. He beat Sally at home, but he still had two more children with her in Raqqa.

The reason why may remain locked inside Sally, along with exactly what she knew and when about Moussa's radicalization.

Remarkably, Moussa suggested they buy slaves: some of the Yazidi girls captured by ISIS in 2014.

They spent $20,000 on two teenage girls, Soad and Bedrine, and a younger boy named Aham.

It was done to keep her company, she says, and to rescue the slaves to a better life. Yet Moussa repeatedly raped the girls.

"When I met Soad, I couldn't think about money. I would have spent every dollar I had on her, to bring her," Sally says.

"But it turned out that she was repeatedly raped by your husband," Walsh says.

"That is true. But in every house that she was in before that was the same situation, but she did not have the support of someone like me," Sally explains.

"Do you now not regret enabling that serial rape?" Walsh asks.

"No, because it would have been so much worse with anybody else," Sally says. "And no, no one will ever be able to imagine what it's like to watch their husband rape a 14-year-old girl. Ever. And then she comes to you - comes to me - after crying and I hold her and tell her, 'It's going to be ok. Everything is going to be fine, just be patient.' I would never apologize for bringing those girls to my house. We knew that if we were just patient we would stick through it together. You understand? I was like their mother."

Astonishingly, Soad sent a message from a refugee camp, confirming Sally's kindness and how Sally was beaten black and blue as she tried to protect her from Moussa.

Yet the terror did not stop there.

Matthew, born in Texas of Sally's first marriage to an American soldier, was a prized cast member for an ISIS film shoot.

"How did Matthew come to be in that video? I recognize him from it," Walsh asks.

"It was not by choice. I ended up with two broken ribs over that video. I fought. I fought. I fought," Sally said.

"What do you remember of that day, Matthew?" Walsh asked.

"It was hard. I did not want to do it. He would hit me, he would stress me," Matthew said.

Moussa died in a drone strike late last year.

"I was able to breathe. I was like, 'OK, we can start phase two,'" Sally explained.

Tens of thousands fled the Raqqa siege, but Sally said she only felt safe at the very end leaving with these last hundreds of ISIS given passage out in a deal.

The FBI has interviewed them, but there are no charges yet, nor tickets back home.

"We want to eat McDonalds. You know, we want to live a normal life for us again," Sally said.

Instead, now she is reliving her decisions over and over again.