The novel has a convoluted plot about two distant cousins both named Allan Armadale. The father of one had murdered the father of the other (the two fathers are also named Allan Armadale). The story starts with a deathbed confession by the murderer in the form of a letter to be given to his baby son when he grows up. Many years are skipped over. The son, mistreated at home, runs away from his mother and stepfather, and takes up a wandering life under the assumed name of Ozias Midwinter.

William Wilkie Collins (8 January 1824 23 September 1889) was an English novelist, playwright, and short story writer. His best-known works are The Woman in White (1859), No Name (1862), Armadale (1866) and The Moonstone (1868). The last is considered the first modern English detective novel.Born into the family of painter William Collins in London, he lived with his family in Italy and France as a child and learned French and Italian. He worked as a clerk for a tea merchant. After his first novel, Antonina, was published in 1850, he met Charles Dickens, who became a close friend, mentor and collaborator. Some of Collins's works were first published in Dickens' journals All the Year Round and Household Words and the two collaborated on drama and fiction.