The Safe House by Cameron Ward

When Jess accepts an offer to caretake a luxury property in the Australian outback, the isolated, all-inclusive solo trip is just what she needs. But Jess isn't as alone as she thinks. As bushfires rage in the distance, strangers start showing up to seek refuge. And as the fires start closing in, tensions in the group begin to rise. Then the phones stop working. All exits are cut off. There's no way out. Quickly, Jess's guests begin to panic. And when the first person goes missing, she realises that someone in the house isn't who they say they are. The danger is already inside...