The intricate relationship of sisters is explored by author Sally Hepworth in The Good Sister.
Her sixth novel, Hepworth has become renowned for writing about family relationships, having written The Mother in Law and currently writing The Step Mother.
Despite having twin brothers and no sisters, Hepworth said she was inspired to write the book while watching her two daughters playing. The book is dedicated to her girls.
"It so quickly turns from squeals of joy to squeals of horror. One minute they are playing and the next Eloise is telling me that Clementine bit her.
"When I went to reprimand her, I'm told by Eloise not to yell at her baby sister. It's like she can do what she wants to her sister, but no one else can," she said.
Thus was born the seed of an idea for The Good Sister, a novel involving sisters Rose and Fern.
Fern works in a local library and avoids crowds and lights, favouring routine and structure. To keep this level, she seeks help and guidance from her sister.
"It was important to me that I wanted the central character to be neuro diverse. The book opens up that conversation which I think is very important.
The book has gained a level of attention from the autism community and I feel I have got that right. So many tell me they have fallen in love with Fern. It is so gratifying," she said.
This dependance however has a dark side, a side which rises to the surface when Fern decides to fall pregnant and gift her sister the baby.
In so doing, she discovers new abilities and her world and friendships blossom in equal measure to her sisters' own surprising dependance on the previous status quo.
"I write in a light style but with an undertone of menace. I like the stakes to be high. Someone has to have something to lose," Hepworth said.
Hepworth said her novels were character focussed with each taking about nine months to write.
The irony of this time frame was not lost on Hepworth who gave birth to her first novel in the same week as having her baby six years ago.
She now works full time as a writer.
The Good Sister is published by MacMillan, to be released on October 27 (Recommended retail is $32.99, paperback).