Each episode follows a multi-layered investigation in which police officers, Civil Aviation or Maritime New Zealand investigators and ESR scientists have worked together to unravel the truth. A New Zealand diplomat is discovered dying from a single stab wound, in a supposedly secure residential compound in Honiara – leaving a crime scene that baffles investigators. Two people lose their lives when a home built plane plummets into the Kaipara Harbour minutes after take off – but why was the experienced pilot so disoriented he couldn't pinpoint his location the night before? A young Japanese student is found floating in a river in Christchurch metres from his home stay address – tragic mischance or foul play?