This novel is one of Wilkie Collins later ones set in the 1870s during the Franco-Prussian war. His heroine, Mercy is deeply flawed. Believing that Grace died due to a German shell hitting her in the head, she assumes her identity. Therefore among her misdeeds she adds identity fraud.
A German surgeon, a totally unsympathetic character, examines the apparently dead young woman & discovers that by operating on Grace, he can bring her back to life. He operates on her in the cottage that the German soldiers commandeer on the borders of France & Germany and takes her back to Germany to observe her recovery. He does say to the medical assistant, that his first operation on a gentleman proved partially successful but the man became insane.
Later Grace travels to England but Mercy has ‘ insinuated herself into the benefactors household. She is well aware of her questionable past.
The themes are that of insanity as appears apparent in Grace who comes to her patroness household and demands that Mercy should be thrown out and she replace her as Mercy has stolen her papers & identity. Mercy’s fiancé, believing her to be Grace Roseberry is as narrow in his outlook as is Grace and in the epilogue we discover that he befriends Grace.
Overall, A telling portrayal of the sexism and discrimination which took place against women during this period – told through the story of a young woman who tries to find a second chance in life, when she comes from the "wrong type of people".