The date is May 3, 1937. The legendary Hindenburg has just left Frankfurt on its final, fateful voyage across the Atlantic. And passenger Leslie Charteris has a terrible sense of foreboding. . . The author of a world-famous mystery series featuring a benevolent sleuth called the Saint, Charteris was puzzled by the overzealous security at check-in—and disturbed to find the Hindenburg under Nazi control. But when an undercover Gestapo agent disappears the next day, it becomes clear to Charteris that his apprehension was not unwarranted. Asked to investigate, Charteris soon uncovers his fellow passengers' most dangerous secrets. But a number of disturbing events occur during the doomed dirigible's final hours—and only Charteris will know what really sparked the explosion that made the Hindenburg go down in flames...