Five women go on a hike. Only four return. When a group of colleagues are forced to participate in a team-building exercise in the Giralang Ranges, they reluctantly start walking down the muddy track. But Alice Russell doesn't appear at the other end. Her last phone call was to Federal Police Agent Aaron Falk. Alice is the whistleblower in his latest corporate fraud case and as he pursues the investigation, Falk uncovers a tangled web of suspicion and betrayal. How well do we know the people we work with?