Two missing backpackers. One vast outback. DS Lucas Walker is on leave in his hometown, Caloodie, looking after his dying grandmother. When two young German backpackers vanish from the area on their way to a ranch, he finds himself unofficially on the case. But why all the interest from the Federal Police, when they have probably just ditched the heat and dust of the outback for the coast? As the number of days the couple are missing climbs, DS Walker is joined by the girl's sister. A detective herself from Berlin, she is desperate to find her before it's too late. Walker remains convinced there is more at play. Working in the organised crime unit has opened his eyes to the growing drug trade in Australia's remote interior. Could this be connected? As temperatures soar, the search intensifies to a thrilling crescendo against the unforgiving backdrop of the scorching Australian summer.