On holiday in the Scottish Highlands, forensic scientist Dr Rhona MacLeod joins a mountain rescue team on Cairngorm summit, where a mysterious plane has crash-landed on the frozen Loch A'an. Added to that, a nearby climbing expedition has left three young people dead, with a fourth still missing. Meanwhile in Glasgow, DS McNab's raid on the Delta Club produces far more than just a massive haul of cocaine. Questioning one of the underage girls found partying with the city's elite reveals she was smuggled into Scotland via Norway, and it seems the crashed plane in the Cairngorms may be linked to the club. But before McNab can discover more, the girl is abducted.