Elephant's work, an enigma

When fed up and thoroughly peeved Chuny causes the train to crash, little does she know that her rage has sparked off a staggering chain of events involving an amnesiac who, in his quest to find a wanted criminal in order to resolve a case of mistaken identity, meets the formidable General de la Costa, learns a great deal about diamonds and becomes embroiled in an extraordinary affair involving the Bishop of Glasminster's mitre.