Death in Berlin — M.M. Kaye

Miranda Brand is a beautiful model visiting Germany for what is supposed to be a month's holiday. But then a story about a fortune in lost diamonds --a story in which Miranda herself figures in a remarkable way--transforms the holiday atmosphere into something more sinister.

A handsome intelligence agent and the shadows from her past throw Miranda into a turbulent whirl of emotions. And when murder strikes on the night train to Berlin, she finds herself unwillingly involved in a complex chain of events that place her life in deadly peril.