I have been hooked on this series since book two. The series started out interesting with the first two books. Then was the build up in books three to four to book five. Now, there common plot - the secret society within the secret society. Each trinity is a link to solving the puzzle. In book seven, there were two new characters introduced that at first seemed like just background characters.
With Delicate Ties, the two characters, especially the one, have a much larger part. As I was reading, I was screaming to myself about the twist that the one character took.
I like the direction the last two books have taken. The Trinities are diverse. The characters are intense and the plot twists leave you blown away.
This is a series that I know I will hate to see end. I have absolutely enjoyed each book and have binge read the series several times. It always is in my top 20 of "recent" books on my Nook.
This book is not a stand alone. Simply because of the plot that started in book five and has wound its way to this book. Also, the characters from previous books make appearances that are important to the plot. I had to go back several books and re-read so I remembered key plot details.