(from: Wilkie Collins: An Illustrated Guide © Andrew Gasson 1998, used with permission)
Magdalen Vanstone is a headstrong girl of 18, with a gift for amateur dramatics. She lives a prosperous and respectable life in the country with her parents, her quieter older sister Norah and their governess and friend Miss Garth. Magdalen falls in love with a weak young man, Francis Clare, the son of an acerbic neighbour. They become engaged, though neither Magdalen's parents nor Clare's father are in favour of the match. Clare is sent first to London and then to China to make his fortune.
The middle-aged Andrew Vanstone and his wife are dismayed when they discover that Mrs Vanstone is pregnant once more. Worse is to follow. Mr Vanstone, on his way to see his lawyer in London, is killed in a railway accident and Mrs Vanstone goes into premature labour on hearing the news; both she and the child die. The family lawyer Mr Pendril breaks the news to Magdalen and Norah that they are illegitimate--they have 'no name'. Their father and mother had only recently been able to marry after the death of Mr Vanstone's first wife in Canada. They are also penniless, since their father had been on his way to sign a new will, essential after his recent marriage. Now the estate will go to his estranged brother Michael Vanstone who vindictively refuses to give his nieces any fair share of their father's fortune.
Norah stays with Miss Garth, their staunch friend, and becomes a governess. Magdalen, resolved to earn her living on the stage, runs away to York. Here she encounters a disreputable cousin by marriage, Captain Wragge, an amiable villain who persuades Magdalen he can help her. She lives with Wragge and his simple-minded wife, and prepares a one-woman stage show playing various 'characters'. Her career, managed by Wragge, is a great success.
When Michael Vanstone dies, leaving no will, Magdalen appeals to his physically and mentally feeble son Noel. She receives a dismissive reply from his formidable housekeeper Mrs Lecount. Determined on revenge, she visits Noel in London, disguised as Miss Garth. Her request for half the fortune is rejected. Mrs Lecount sees through her disguise and snips a piece of cloth from her dress as evidence.
Magdalen now decides to retrieve her inheritance by marrying her cousin Noel--her engagement to Francis Clare has been broken off. With Wragge's help, she follows Noel to Aldborough and is introduced as Wragge's niece, Susan Bygrave. Mrs Lecount is again suspicious but Wragge lures her away to her family in Zurich with a forged letter. Noel is fascinated by Magdalen and proposes. Magdalen, horrified at the prospect of marriage to a man she loathes, buys a lethal dose of laudanum and contemplates suicide, but finally goes through with the match.
Mrs Lecount returns and convinces Noel that he has been deceived into marrying his cousin. Finding Magdalen's bottle of laudanum, she also persuades him that Magdalen planned to poison him. Noel alters his will, leaving the fortune to a cousin, Admiral Bartram, with a secret trust passing the inheritance to the Admiral's son George Bartram, on condition he marries within six months. Noel, who has a weak heart, collapses and dies.
Magdalen, convinced that the legacy to Admiral Bartram conceals a secret intention, disguises herself as a maid, and takes a position in the Admiral's house. She narrowly fails in an audacious attempt to find the concealed letter and escapes to London. Penniless and desperately ill, she is nursed back to health by Captain Kirke, whom she first met at Aldborough. They fall in love and marry. Meanwhile Norah, without knowing anything of the will, has met and married George Bartram.