In The Black Castle (1952) Sir Ronald Burton, a British gentleman, investigates the disappearance of two of his friends at the Austrian estate of the sinister Count von Bruno, who is hunting unsuspecting English visitors a la The Most Dangerous Game, for past grievances against the British Empire.
Burton arranges to be one of Bruno’s “guests”, although Bruno knows nothing of his friendship with past victims. This all comes out in the denouement, when Burton reveals the truth to Bruno just before he kills him in revenge for his friends and countrymen.
In my twisted version, Burton is pursuing the two men he claims are “friends” to exact vengeance of his own. He tracks them to Bruno’s castle, and when he realizes Bruno has robbed him of his vengeance after so many years and so many hardships, he kills the nefarious Count.