When Kate's aunt shows up unexpectedly to grant all her wishes and take her to her uncle and cousin, she thinks her fairy godmother has arrived. However, she soon finds a house filled with frightening secrets. This Heyer novel imparts the kind of creeps worthy of Victoria Holt or Phyllis Whitney. However, the witty dialogue and humor full of Regency mannerisms still sets the stage. The ending is a departure from other Heyer tales; the climax isn't neat and pretty. However, the symmetry and sense are still present.
Cousing Kate touches on the way mental illness was stigmatized and treated in the 1900's. Also, we learn a lot aobut the life of woman "following the drum" with their military men.
I devoured this novel in a few hours. Mystery addicts will like this; I couldn't have guessed the ending. Romance readers should look elsewhere. The endings to Heyer novels give the reader a feeling that we are interrupting a conversation and decide to discreetly creep away. I don't know another author who uses this technique.