When Emily Thornton discovers a will linked with the murder of a sea captain in Hull in the 1860's, she is determined to discover what happened - but a vital witness is missing. So, Emily enlists the help of Thomas Laycock, a young man who has come to Hull to open his own detective agency. As the pair travel to Middlesborough and Whitby, the investigation unfolds, and their attention is brought to a locket worn by a mysterious young woman. Emily and Thomas are convinced that this is a crucial link in the case. Can they unravel the meaning behind this unusual locket? And escape the danger following them every step of the way . . .