The finale to this trilogy does an excellent job of concluding plot threads from previous books on multiple levels. David and Murdo have grown as people and grown closer together, but some roadblocks (internal and external) still stand in the way of their happily every after. When both of them must travel to London, they confront these issues head-on in a way that was both unexpected and completely satisfying.
The overall message of this book is finding love and acceptance outside of borders proscribed by society. This applies to a few different relationships in the book, and the sacrifices characters must make to achieve their goals (even when those goals are not what society says they should be).
But through it all, David and Murdo realize their true goals involve each other. They open up to each other in ways that would never have been possible in the first book of this trilogy, and I’m happy these two characters joined together to find their happiness against so many odds.