Mr Sabin, an old exiled French duke, lives happily in Massachusetts with his wife Lucille, until the day she disappears in New York. Anonymous letters, written in yellow crayon, order him to return home. The crayon is the mark of a secret society of European nobles, determined to halt the rise of the socialists.
Mr Sabin follows Lucille to London, where the society is using her to influence a powerful minister. Alone, this old man stands up to a formidable organisation, amid elegant drawing rooms and political intrigue.
Full of suspense, this novel is easy to read in the language you are learning.
