Sinister.  That is the overriding mood in this story. 

< the soft clacking footsteps that would come from a pair of fine oxfords

An ominous intrusion into the conspiratorial conversation. And the seemingly benign comment,

>There you two are, I was just about to make a toast without you

Carries the weight of impending danger.  There is the sense that the characters are in the grip of something beyond their understanding and will be swept away by forces not yet clear to them.