Samuel Melton, designer of the new British aircraft, the Thunderwing, was distraught when the fifth jet crashed into the Indian Ocean. Bob's search for the reason behind the crashes took him to Aden, where two attempts are made on his life. Bob borrows a plane and does reconnaissance work to bring to justice hypocritical Jeremy Binderley, an ostensibly reputable citizen who is in reality head of an opium smuggling ring. The narrative here takes every corner on two wheels, bringing Bob up against a terrifying new aircraft able to take off and land in crevasses. It is for the librarian to decide whether a story which brings Bob into an opium den will be acceptable in her community.