Smugglers of a powerful methamphetamine, nicknamed "dilithium crystals", by speedboat and light aircraft kill themselves rather than be caught by Customs. Nick Storey, Collector London Port, identifies patterns of evidence and smuggling routes by small ships and light aircraft, which lead to several dubious businesses in South Essex, a City investment company and a Belgian security firm with antecedents in African mercenary operations. Tracking light aircraft movements to small airfields uncovers smuggled krugerrands and a longstanding feud between Derek Clyne (son of "Frank the skin") and a rival, Benny Drew. To pressurise the suspects, Nick gets them together unawares, unwittingly causing a bloody conclusion. But that only serves to provide cover for the real crooks, masterminding a huge fraud. "Eight Miles high" is the twentieth book in a series of detective stories set in HM Customs & Excise, by Richard Hernaman Allen, a former Commissioner.