So I started this series nearly 3 years ago when I discovered the first book, Mister Monday. I read through the first 6 but since #7 wasn't published yet, I had to wait. Then I forgot all about the series until recently! I had forgotten nearly everything about the books. And since #7 picks up exactly where #6 left off, I was a little lost at first. My mind was somewhat refreshed as I read this final book, and I thoroughly enjoyed it. It was well written. The first young adult fiction I've read this year.
Anyway, the book is about Author Penhaligon as he's basically pulled into another dimension of sorts and put on a mission the restore something called the Will, broken into seven pieces, in seven parts of the House, guarded by seven trustees. Each trustee also guards a key, hence the title of the series. Each trustee, who's namesakes are the titles of the seven books, possesqualities of the individual seven deadly sins. And the book basically takes place in seven days.
I didn't care much for the ending, but being an allegory of sorts, I guess it was appropriate. I was definitely not as disappointed with the end of this book as I was for the ending of the Harry Potter series. I just felt bad for the protagonist, Arthur.
Anyway, I give it 4/5 stars on Goodreads because I enjoyed it and read it in a day.