It begins with her decision, at 20, to "devote her life to God," when one Sunday morning, during confession, her local parish priest asked if she'd ever thought of becoming a nun.
As the youngest daughter in a family of eight, born to a mother who had "breathed God's love into every cell of my being from the moment of my conception" a religious vocation appealed.
"I thought about the idea of dedicating my life to God as a nun. Somehow, the sacrifice, the commitment and the practice of Christian virtue seemed worthwhile."
From these years of faithful devotion, a picture emerges, of a young woman searching for a purpose, for a place in a religious institution going through its own turmoil of a controversial liberal shift, combined with an increased number leaving the faith.
Ms Hall's first years as a novice in the Roman Catholic order of the Sacred Heart were marked by a sense of loneliness, with few peers her age and elders who gave little away in terms of advice or comradeship.
"As a teenager I had been so vivacious, the liveliest girl in the parish, but I had changed. Living with nuns had turned my focus inwards, making me introverted."
Then came a dark point in her life, when a man she befriended took advantage of her and left pregnant with a baby boy she gave up for adoption.
Vulnerable, she turned to her religious elders for support only to be dismissed and told her vocation was no longer. "You do not have a vocation...If you did, this never would have happened to you," said a senior priest.
Left floundering, as a mother without a child, a woman of faith without a calling, the promise of a new life as a Palmarian nun beckoned warmly - only for her to once again be left in the cold once enclosed in the convent walls.
Established in the 1970s, after four young girls claimed to have seen a holy apparition on farmland near the village of Palmar de Troya, the Palmarian church has distanced itself from Rome; it's created its own rites, liturgies and its own bible.
Ms Hall's life within it was dominated by religious rituals, sleepless nights, punitive regimes and temperamental superiors.
The daily routine was controlled by tolling bells, endlessly gruelling domestic tasks all done in the compulsory silence enforced outside of prayer or song.
She slept in a tiny room, with a threadbare blanket on a wooden bed, wore ill-fitting hand-me down clothes and shoes and was cut off from friends, family and the rest of the outside world, with no television, radio, newspaper or telephone.
When her father and sister did one day make the trip across the world to visit her, she was only allowed to see them only twice in her ten minute breaks. "Many years later she [my sister] told me that she felt like I had died."
Eventually this thankless commitment eroded what was left of her once unfaltering faith. She left and was cast out of the convent with nothing but a plane ticket home, some money and a shoulder bag containing her bible, writing pad and passport.
At home, in New Zealand, Ms Hall had to "relearn" what it meant to be human. She recalled standing in a bar, holding a glass of wine at a loss of how to act.
"I'd been a Carmelite nun, which means solitude, silence, a very hard-working regime and no conversation ever. So you are just locked in your own thoughts."
She likened this belief in her former life to the fundamentalism behind violent extremist groups such as ISIS.
"I so understand terrorists, because I used to be fanatical in another way. I never picked up a gun - but I was trying to create peace in the world through prayer. I believed in prayer like these people believed in terrorism."
Over time she's learnt what it means to be human, returned to work for some years as a music teacher before retiring and has even made contact with the son, she gave up so many years ago.
She no longer has faith "in a God above", but says she puts her faith in the people around her.
"At night time, whenever I woke up...until the last few years, I always talked to God. Now I don't...because I don't need to talk to him, it doesn't really matter if he exists or not. Now I talk to myself."
Now she relies on her own strength, takes comfort from those around her and pleasure from the natural surrounds of her North Shore home, where she lives with her partner.
The Palmarian Church
• Considered to be a cult
• Started in the 1970s after four girls claimed to have seen a holy apparition on farmland near the village of Palmar de Troya
• It has created its own rites, liturgies and bible
• To learn more on Ms Hall's story go to www.mariahallwriter.com
