On the lonely beach below a posh house overlooking the ocean in Cornwall, England, a body is found brutalized and abandoned. Though on the property of James Duncan, a wealthy mine owner, Duncan reports that the night previous to the body being found, he also was accosted in his home, where he narrowly escaped with his own life before frightening off the intruder. But Duncan, himself, holds a terrible secret, one that has tormented him for years. And though he seeks the aid of famed detective, Sexton Blake, to help iron out his past, there are forces at play with much greater and more sinister ambitions. And they will not stop until Duncan's seemingly ordinary mine is in their possession.