'You know you’re gonna die': How a teen survived Australia's worst serial killer couple.

Kate Moir was 17 years old when she was kidnapped and repeatedly raped by a couple who would become known as Australia’s worst serial killer duo: Catherine and David Birnie.

Moir accepted a lift home from the couple on November 9, 1986 after a night out with friends. She soon sensed danger and was kidnapped at knifepoint.

Moir - now 47 - has shared harrowing details of her abduction for the first time on television for Channel Seven's new crime show, Murder Uncovered.

Moir revealed she asked her captors,  "Are you going to rape me or kill me?" when she was abducted.

The reply was: "We'll only rape you if you're good."

Catherine and David Birnie had already murdered four women - Sussannah Candy, 15, Denise Brown, 21, Mary Neilson, 22, and Noelene Patterson, 31 - in the four weeks before they abducted Kate Moir.

She was to be their fifth victim.

Moir told Channel 7 she realised her chances of survival were slim within the first two hours of her  capture.

"You know you're gonna die but you don't acknowledge that to yourself, you just live it," she said.

After making her watch the movie Rambo, Moir was made to shower.

"I remember thinking it was weird to make me shower before they raped me," she said.

"They made me dance in front of them to [Dire Straights song] Romeo and Juliet. It was two hours of mental torture. I cried when I danced."

David Birnie raped Kate for the first time not long after midnight while his wife Catherine watched and took notes.

She was made to sleep in the couple's master bedroom, with her foot handcuffed to David's. Moir says she was offered pills to help her sleep.

"I thought if I went to sleep I’d never wake up," Moir said. She hid the pills under her tongue before hiding them under the mattress.

Kate managed to escape through a window the next morning when David went to work. A knock on the door distracted Catherine, who had forgotten to secure Moir in the house.

Kate ran to neighbours' doors, knocking on three of them and being attacked by a dog before she found a man standing outside a store.

"I said ‘Help I’ve been raped. Please take me inside and call the police. If a woman comes here and says I’ve had a fight with her and I’m her daughter, don’t believe her. I’ve been raped," she said.

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The Birnies were sentenced to life in prison for the murders and for Kate's abduction. David hanged himself in prison in 2005, but Catherine is eligible for parole within a couple of weeks.

"If that woman had an ounce of decency she would have made some effort or showed remorse," a retired detective Paul Ferguson told Seven News.

"This woman does not deserve one day of freedom."

Murder Uncovered airs on Channel Seven at 9pm on Wednesday.