Dorothy's Double The Story of a Great Deception, Volume 2-G. A. Henty

On a trans-continental train journey into Paris, Max, a young adventurer determined to make his way as an artist, meets Blake, a well-to-do Irishman. Blake helps Max set up a studio in Montmartre and they enjoy the life of Paris and each other's company. However, things are definitely not what they seem and the book takes a very contemporary turn as another person appears on the scene. - Summary by Simon Evers