Gareth St. Clair is in a bind. His father, who detests him, is determined to beggar the St. Clair estates and ruin his inheritance. Gareth's sole bequest is an old family diary, which may or may not contain the secrets of his past--and the key to his future. The problem is, it's written in Italian, of which Gareth speaks not a word. When Gareth crosses paths with Hyacinth Bridgerton at the annual Smythe-Smith musicale, she offers to translate his diary, even though her Italian is less than perfect. Hyacinth is fiendishly smart and devilishly outspoken, and according to Gareth, probably best in small doses. But there's also something about her--something charming and vexing--that grabs him and won't let go. As Hyacinth and Gareth delve into the mysterious text, they discover that the answers they seek lie not in the diary, but in each other.