Battle for the Abyss

This book by Ben Counter is the eighth Horus Heresy novel in the series, and the first to feature precisely zero primarchs! Outrageous! Where are our oh-so-flawed demigods? Trust me when I say this book proves you don't always need one around to have an adrenaline-fuelled violent romp through space. In this instalment, the recently (and essentially, secretly) heresy-aligned Word Bearers have received from the shipyards of Jupiter the largest spacecraft ever commissioned in the Imperium's history - a ridiculously big behemoth called The Furious Abyss - and, surprise surprise, they plan on using it to lead a sneak attack on the Ultramar system, a core of loyalist Imperial worlds under the protection of the Ultramarines Legion, so crippling a vital centre of Imperial control before news of the heresy has even reached Terra yet. Events conspire to draw the Abyss into conflict with a loyalist cluster fleet, and a chase through the warp ensues - with a small contingent of the loyalists managing to infiltrate the Word Bearers' ship but with little they can do to stop it from achieving its goal. A haphazard, uncoordinated but determined series of efforts between Ultramarines Captain Cestus, Space Wolves Captain Brynngar, World Eaters (apparently this book takes place before their legion goes full heretic) Captain Skraal and Thousand Sons psyker Mhotep is all that stands between the Abyss and Ultramar - the stakes may not be as high in scope as they have been in most of the previous novels; no allegiances are being traded here, everyone stays standing where they stand - but it's the first sign of the heresy metastasizing past the watersheds of Isstvan and becoming a full blown civil war spanning the Imperium.