Whither Thou Goest by William Le Queux (1864 - 1927)

The Earl of Saxham was vastly annoyed when his son, Guy, fell in love with a “penniless nobody,” and announced that he would marry her against all opposition. He determined to separate the lovers; to which end he persuaded an influential friend in the Foreign Office to secure an appointment for Guy in the Embassy at Madrid. He little knew that he was sending his son into the centre of a hotbed of anarchism, that Guy’s footsteps were to be dogged by a vindictive and revengeful woman, that his life was to hold many a thrilling moment and not a few narrow escapes. (Summary from the Prologue of the book)