This book is so thrilling! I love how it's so much more different than the MI series because it's way before the time and they are fighting a whole different war. There are many of the main (older) characters from the MI series in this series. They, of course, are younger and have so much more backstory in this book. I love how it connects the books in this one way. Although, the MI series is more of an Angel-vs- Demon war and this book is more a shadow hunter vs. mechanical (ie. robot) war.