James Swallow seems to be a hit a miss author for me. I don't really care for many of his Blood Angles books, but I really enjoyed Flight of the Eisenstein. I believe that Mr. Swallow should stick with the Horus Heresy novels because Nemesis is a very good read.
The book feels like part detective novel and part Dirty Dozen. There is a serial killer that is being tracked down by local law enforcement on a sleepy little world that has largely untouched by the heresy. We also see the an execution force put together by all of the different sects or "clades" of assassins on Terra. These killers are sent to kill the Warmaster and stop his insurrection before it can continue any further.
I am usually not a fan of, "two books in one" that we often seen in the Black Library stories, but this one wasn't so bad in my opinion. For one thing, the two stories were merged together pretty quickly, and for another thing, both threads were just so damn interesting I wasn't left upset when they story switched gears.
The Horus Heresy books are always interesting to me as we generally know what is going to happen at the end. We KNOW that the execution squad will be ultimately unsuccessful in killing the Warmaster, but Swallow does a good job of weaving a story in there that still feels as if it has a successful conclusion even if Horus does survive.
I give this book 4 neural shredders to the brain pain out of 5.