Once Night with a Spy [Celeste Bradley]

One Night with a Spy (Royal Four, Book 3) - Celeste Bradley

I spent half of this book waiting for the moment of shock when Marcus realized he was wrong about Julia and there wasn't one! At least he wasn't as much of an ass as Dane was in the last book (although he did have his moments!)

I think I'm going to have to read the Liar's Club books, since every time one of them shows up in one of these I'm completely lost