Radiant Heat by Sarah-Jane Collins

When a catastrophic wildfire suddenly rips through a woman's hometown, she thinks she is lucky to have survived . . . until she finds a dead woman in her driveway, clutching a piece of paper with her name on it. . . .
The blaze came out of nowhere one summer afternoon, a wall of fire fed by blustering wind. Yet, somehow, Alison is alive. She rode out the fire on the damp tiles of her bathroom, her entire body swaddled in a wet woolen blanket. As flames crackled around her, the bitter char of eucalyptus settled in the back of her throat, each breath more desperate than the last.
The wildfire that devastated the Victoria countryside Alison calls home sets in motion a chain of events that threatens to obliterate the carefully constructed life she is living. When Alison emerges from her sheltering place, she spots a soot-covered cherry red car in her driveway, and in it, a dead woman. Alison has never met Simone Arnold in her life . . . or so she thinks. So what is she doing here?
As Alison searches for answers across Australia's scorched bushlands, she soon learns that the fire isn't the only threat she's facing. . . .