Aunts Aren't Gentlemen by P. G. Wodehouse

Sent to the countryside to rest after developing a mysterious rash, an affable but hapless bachelor is swept into a comic feud over a racehorse’s fortunes that hinges on the kidnapping and counter-kidnapping of a black cat. With an imperious aunt issuing orders, a blustering sportsman stirring trouble, and romantic entanglements threatening to land him in an unwanted engagement, his unflappable valet engineers a neat sequence of stratagems that outwit all parties, calm the village, and see his employer safely extricated.