I really look forward to each Horus Heresy book I can get to and this one really did not disappoint. Granted, the Heresy really took off with the first 3 books, then there's been stories pertaining to this first trilogy since then, but this one was a very interesting "side" story that has huge implications for the galactic civil war portrayed in this saga. Kai Zulane, astropath, has been entrusted with an extremely important piece of information concerning Horus Lupercal's treachery against the Emperor. The problem is he does not know what it is as it has been psychically buried deep within him. This makes him a wanted man, as an outlaw group and others close to the Imperium on Terra are after Kai to use this information. The "Outcast Dead" are imprisoned Space Marines from various legions that seize Kai and set out on a mission to escape from Terra and get Kai to Horus in an attempt to reveal this information he has. The ending is a real bombshell where the Heresy is concerned, and I really enjoyed seeing where Kai ended up as some real nasty battles occur between the Marines and the outlaw group. A worthy addition to the Heresy, IMHO.