Abby Hernandez was just 14 years old when she was kidnapped on her way home from school in 2013.
For nine harrowing months, she was held prisoner in a shipping container by a monster in New Hampshire.
"He told me, 'Call me 'master,'" she told ABC’s "20/20” in an interview airing Friday night. “He said, 'You know, I’m thinking of finding something a little more humane for you to keep you quiet, I’m thinking of a shock collar.'"
She said he later put the collar around her neck and told her to scream. When she did, it shocked her.
ABC News Correspondent Deborah Roberts told Inside Edition that Hernandez’s story resonated with her.
“I have a daughter who is the same age as Abby. To hear her talk about what she went through and how she was able to survive and how she was preyed upon — it affected me, not only as a journalist but also as a mom,” she said.
The horror ended as suddenly as it began. Fearing police were about to arrest him, her kidnapper, Nathaniel Kibby, released her on a lonely New Hampshire road in 2014.
“I remember looking up and laughing and being so happy,” she told "20/20."
Security cameras captured the moment she found her way home, moments before she reunited with her mother.
Hernandez’s amazing story has striking parallels with the 2016 kidnapping of Kala Brown, who was held captive in a shipping container on a on a South Carolina farm for more than two months by serial killer Todd Kohlhepp, until she was discovered by police.
Police used bolt cutters to free Brown, who — just like Hernandez — survived the ordeal and is now building a new life.
Hernandez’s interview will air Friday, Sept. 7 at 10 p.m. ET on ABC’s "20/20."