Once Every Never by Lesley Livingston
Clare had been around her aunt long enough to know the rules where antiques were concerned--most of which started with the phrase "NO TOUCHING" and ended with the phrase "NO TOUCHING" and usually included the admonition "UNDER ANY CIRCUMSTANCES" and the word "EVER."
"'Zot' doesn't work for you?" Milo smiles faintly.
"Okay, Milo," she said quietly. "Hand over the reins to Connal. It's not a sports car anymore, it's a war chariot. And he has to be the one driving."