Meet our hero: Gareth St. Clair is in a bind. His father, who despises him, is determined to ruin the St. Clair fortune and destroy his inheritance. Gareth's only legacy is an old family diary that may hold the secrets of his past and the key to his future. The problem is: it’s written in Italian, and Gareth doesn’t speak a word of it.

Meet our heroine: Society unanimously agrees that there is no one quite like Hyacinth Bridgerton. She is devilishly clever and devilishly charming in small doses. But there is something about her – something charming and infuriating – that captivates him and won’t let go.

Meet poor Mr. Mozart: Or perhaps not. But rest assured, he is spinning in his grave as Gareth and Hyacinth encounter each other at the annual – and annually discordant – Smythe-Smith music evening. For Hyacinth, every word from Gareth seems to be a challenge, and she offers to translate his diary, even though her Italian is slightly less than perfect. Yet as they delve into the mysterious text, they discover that the answers they seek lie not in the diary, but within each other – and that there is nothing so simple – or so complicated – as a single, perfect kiss.