S4·E11 Don't Buy from Me, Argentina

Helen is hosting a party for Argentinian polo players at Woodcote Park. She falls for Raoul Gomez, a suave Argentinian. Aiden Curtis, the husband of one of the English guests, asks Ken to watch his wife Merrily (!) who is ""terribly easily influenced"", meaning that he knows every man in the room fancies her and that he thinks she is having an affair. Ken follows her and uncovers a conspiracy between her, a local vet, David Rennet, and one of the Argentinian polo players, Celestino da Silva. Merrily's horse, Deauville Dancer, is infertile but Rennet has signed a certificate stating that it is in perfect health. She ""sells"" the horse to da Silva, thus establishing its value so that the insurance company will pay out when, six months from now, Rennet ""has no choice"" but to have it destroyed. She arranges to return da Silva's money when the insurance company pays up, but instead she leaves him as the owner of an infertile horse and disappears by plane with his money, accompanied by another