When John Horbury, the manager of a small bank in an English market town, disappears at the same time as some valuable jewels and securities from the bank, the bank's owners refuse to call in the police. When Mr Horbury's niece arrives she enlists the assistance of the chief clerk and insists on a top detective from Scotland Yard being assigned to the case. Together they investigate whether it is a simple case of embezzlement or something more sinister. When a body is found at the bottom of an abandoned lead mine, is this the solution to the mystery or will matters become more complicated?