— The rubies!
Anton Walbrook's cruelty towards Bella is scarily thrilling to watch and bewitching in the worst way here, making the viewer complicit in his obvious sadism. His forced, barked laughter at Nancy whilst Bella is in the room is sharper than the knife she herself will later wield, and I have no idea how his dangerous flirtations with Nancy on the stairs got past the censors. Walbrook's portrayal of Paul gets less and less enjoyable to watch as the film goes on and his character becomes more desperate, and, well, the abuse becomes less artful, reminding the viewer that, yes, you might have disliked it before, but you can't deny you found it stimulating at first.
Absolutely the superior Gaslighthuman portrayal of a dangerous and violent narcissist. Furthermore, Cukor's version has Bella only ironically taunting Paul/Gregory with the knife, whilst Thorold Dickinson has us nearly convinced that she will actually do it. Finally, Walbrook's delivery of "The rubies!" is superb, and no doubt inspired Walbrook and Dickinson's ending of The Queen of Spades (1949).
Synopsis: Twenty years removed from Alice Barlow's murder by a thief looking for her jewels, newlyweds Paul and Bella Mallen move into the very house where the crime was committed. Retired detective B.G. Rough, who worked on the Barlow case, is still in the area and grows suspicious of Paul, who he feels bears a striking resemblance to one of Barlow's relatives. Rough must find the truth before the killer can strike again and reclaim his bounty.