**SPOILERS** One of the most unusual and unpredictable of "The Whistler" movies that has to do with burnt out industrial and banking tycoon John Sinclair, Richard Dix, who after working himself into an early grave, in making his millions, finds out that he'll soon and up in one if he doesn't get his act together and take a long vocation from his work.
Going to his rented island vacation house off Chicago's Lake Michigan Sinclair has a sudden seizer and ends up in Chicago cab driver's, who gave him a lift, Erin Sparrow, Rhys Williams,next door hotel room. Despite his phenomenal success in the business world Sincleir never had a chance to develop any lasting relationships and is in fact, despite his many millions, all alone in the world. It's Sparrow, a former English lightweight boxing champion, who shows the clueless Sinclair, who now calls himself John Carter, what friendship is all about and how to make friends as well has his, Sinclair, ability in influencing people to invest in his banks and businesses.
Having a new lease on life Sinclair easily makes friends with a number of people that he comes in contact with in Chicago including registered nurse Joan Martin, Lynn Merrick, who Sparrow introduced him to. Not really being that hip in Joan's future with her long suffering fiancée Dr.Fred Graham, James Cardwell, who's trying to open up his own practice, he works almost for nothing at a local charity clinic, Sincalir make Joan a proposal to marry him and move into his new home away from home a converted, with all the modern convinces, lighthouse off the coast of Maine.
A destroyed Dr. Graham leaves Joan feeling that her marriage to Sinclair, with him not expecting to live for more then six months, so that she could inherit his money is incredibly greedy as well as unfeeling towards him. It's when Sinclair's health improves and his sudden death, predicted by his doctors, doesn't come to pass that things start to get a bit stressful for everyone involved including Dr. Graham. The doctor unexpectedly showed up at the lighthouse expecting Joan to come back to him, after her husbands John Sinclair's demise, as well as as also getting himself a piece of Sinclair millions.
The movie "The Voice of the Whistler" then takes a turn for the worse for everyone involved with Sinclair and Dr. Graham plotting each others murder with Joan, who's caught in the middle of all this, not Sinclair's money being the ultimate prize.
****SPOILER ALERT FROM THIS POINT ON****You never know what's coming next but when it does it will shock your socks off. Sinclair for all his smarts let's the cat out of the bag in giving Dr. Graham the idea to murder him. It's that idea on Sinclair's part that leads to the double disaster at the conclusion of the film. If Sinclair was honest with himself he would have left Joan alone and not think that he could buy her like the many expensive, homes cars and yachts, items he bought for himself all through the years.
In he end Sinclair overestimated himself in trying to outsmart Dr. Graham and giving him the opening that he needed to put him away for good and thus have Joan all for himself. It wasn't that Dr. Graham saw through Sinclair devious and murderous plan but that Sinclair, always feeling that he's in complete control, overlooked some very vital things, like the nailed shut lighthouse windows, that in the end lead to his downfall.