Having been held captive, beaten and sexually violated for nearly 24 hours, a 19-year-old woman's life nearly ended in the Dome Valley last May.
There Wayne Blackett attempted to break her neck before sending at least 10 blows with a hammer crashing into her head.
Nicola Jones and Julie-Ann Torrance were nearby, chortling with laughter and Jones possibly even holding a torch to allow Blackett to see in the dark, prosecutors say.
On Monday, a jury at the High Court at Auckland took five-and-a-half hours to find the pair guilty of attempted murder, while Blackett had pleaded guilty to the charge at the start of the trial.
Jones was found not guilty of also sexually assaulting the woman.
Prosecutors said the woman's survival was "nothing short of a miracle".
Despite the hammer blows fracturing her skull and depressing her brain by 2cm, she was found unconscious, yet alive, the next morning after the trio left her for dead by a road north of Auckland.
Waking in hospital one week later, the now 20-year-old was partially paralysed and needed to learn to walk and talk again before going on to be the key witness in the trial of Jones and Torrance.
Neither the victim or her family spoke to the media after the verdict, but the court had heard Jones acted out of a deep hatred for the young woman, despite once considering her a sister.
She thought the woman had slept with her partner and urged child protection teams to remove her children, while Torrance thought the woman had stolen items belonging to her daughter.
The women were also "fuelled" by methamphetamine, prosecutors said.
They began their attack when, together with Michelle Blom and Jacyln Keates, they grabbed the woman from Auckland's Karangahape Road and drove to Blom's house.
There in the basement they stripped the woman naked, cut her hair, beat her, stomped on her hand and put a cricket wicket into her anus and then her mouth, the prosecutors claimed.
While Jones was not guilty of sexual assault, she and Torrance pleaded guilty to the kidnapping and assaults.
Blom was found guilty only of kidnapping, while Keates was earlier sentenced to three years and two months in prison for her role in the attack.
Jones and Torrance also pleaded guilty or were found guilty of attacking, robbing and tasering the young woman in a separate incident in April 2016.
A sixth accused, Cameron Hakeke, was found guilty of kidnapping and assaulting the woman during the same April attack.
All four have been remanded in custody until sentencing on April 28.