When a murder occurs in Mr. Audley's Asylum for the Troubled, the blame falls on a patient known as Mad Laurie. The police are ready to embrace this answer and Mad Laurie is hastily put in chains, but there is one who isn't quite so sure that the old woman is to blame. Maud Chapman is a humble spinster, living in a respectable London apartment, and when she reads of the murder in the papers, she's not satisfied with the conclusion. Using the alias of Grace Cooper, Maud gets a job as a cook at the asylum and decides to investigate the case, but what she finds will uncover secrets that she could never have dreamed existed...