This isn't the story of one happy couple -- but four couples. Thus, we see the reason for the title, "Cotillion," 4 couples engaged in the dance of love. Kitty Charings has spent her life secluded in the country, pining for a London season and the love of handsome Jack Westruther. Of course, Jack is aware of her feelings but he's too busy being a rake to worry about Kitty right now.
Matthew Penicuik, Kitty's skin-flint guardian, has decreed that he will be giving his considerable wealth to Kitty -- if she marries one of his grand-nephews. When Jack (one of those grand-nephews) doesn't arrive to ask for Kitty's hand, she plots a way to get a season in London and some revenge on Jack. She asks another cousin, Freddy Standen (a cousin not interested in marrying and not needing Kitty's windfall), to conduct a counterfeit engagement with her.
Now, Freddy has great fashion sense and is a fine dancer, but he's not brilliant or handsome. But he's too nice a guy to hurt the feelings of Kitty, so he reluctantly agrees. Since he has a family in London, he agrees to take her to stay at his parents' home and escort her to-and-about London for a month. While becoming part of the social swirl, Kitty meets some secondary characters that give Kitty and Freddy the opportunity to learn more about each other and themselves.
Unfortunately, I listened to this book and the reader did not bring forth the sparkling dialogue that I'd heard so much about. I plan to read it again later (but not by hearing it read). I missed out on the scintillating dialogue that other reviewers have been gushing about. Perhaps there are times when a book must be read to get the full import.