Katy Sweeney is looking for her sister. A year earlier, her free-spirited younger sister, Phoebe, vanished without a trace in Western Australia. With no witnesses, no leads, and no DNA evidence, the case has gone cold. But Katy refuses to give up on her. Using Phoebe's social media accounts as a map, Katy retraces her sister's steps. Was Phoebe being followed? Who had she met along the way? And then Katy's path collides with that of Beth, who is on the run from her own dark past. Katy realizes that Beth might be her only chance of finding the truth, and the two women form an uneasy alliance to find out what really happened to Phoebe in this wild and perilous place.