On a certain cold evening in January, and just as the Scotch night-mail was about to start for the north, a stranger drove up to Euston and alighted, and was glad enough to escape from the chill draughts of the echoing station into the glow and warmth and comfort of a sleeping-car. He was a man of means apparently; for one half of this carriage, containing four berths, and forming a room apart, as it were, had been reserved for himself alone; while his travelling impedimenta-fur-lined coats and hoods and rugs and what not-were of an elaborate and sumptuous description. On the other hand, there was nothing of ostentation about either his dress or appearance or demeanour. He was a tall, thin, quiet-looking man, with an aquiline nose, sallow complexion, and keen but not unkindly gray eyes.