One of the better outings for Roland Winters as our unflappable Hawaiian sleuth. This time he has to fathom a mysterious conspiracy that has turned a loss-making hole in the ground into a worryingly profitable mine - and the owner feels certain that he is about to get his comeuppance. We see quite a bit more of No. 2 son "Tommy" and "Birmingham Brown" in this one - and they add quite a bit to his actual quite clever little Monogram mystery.
