Sherlock Holmes and Dr Watson receive a visit from a client by the name of Mrs Fairfax. She is highly concerned about the welfare of her sister, Miss Dorothy Davenport, and enlists their help. Mrs Fairfax tells them her sister left London suddenly and is now in Devon, apparently enjoying a holiday she won. Taking off on such notice is completely out of character for Miss Davenport, and her sister is worried Dorothy has been lured away for dubious reasons. Holmes and Watson begin to make investigations into the abrupt absence of Miss Davenport, and soon discover that the holiday could, indeed, be a ruse. But who would want Miss Davenport in Devon? And at such short notice? As they delve deeper into the mystery, they realise that some people in Dorothy's life are not to be trusted. Can they solve the mystery before things take a turn for the worse?