At Chilford Green Aerodrome, a small, privately owned airfield in the heart of England, the transportation of cargo takes place daily. But this is no ordinary cargo – as 18-year-old Chris Lomax is to discover. A keen motor mechanic whose enthusiasm for aircraft has prompted him to get a job at Chilford, Chris’s self-reliance and questioning mind are soon causing consternation for his employers; as he gets alarmingly close to the true nature of the airfield’s operations, it becomes clear that Chris – and his young colleague, Sarah – could be in serious danger.