Your heroine's never been a cat person. She's never had a pet, and views all animals with mixed alarm and confusion. But when a starving, boney cat shows up on her doorstep, she takes him to the vet right away. She's not a total monster–and when she sees how cute the vet is, she wonders if she could warm up to cats. Or dogs. Or parakeets–he really is that cute.
Your hero became a veterinarian to help those without a voice–and because he was self-conscious about the inheritance that paid for his schooling and cushioned his low salary. Nobody knows he's the heir to the mysterious Caldwell-Belgiorno billions, and he's scared what would happen if they found out. But when a winsome brunette shows up with a starving feline in tow, his heart opens before he can stop it.
How do they dance around what they're hiding (her: her antipathy to animals; him: his money)? What happens when these secrets are revealed? Maybe instead of pretending to like cats, she pretends not to be allergic. What's the poor cat's name?