Are they re-taking waterworld? Oh wow, yes they are! And other places too! Deathwatch (humanity's finest!) teams are showing up on Ork infested planets with orders to capture Ork witches. And it's possible to detain those Orks without exploding because the Deathwatch teams are backed by the Sisters of Silence! But why are they trying to capture Ork witches? It's part of a plan so silly it could only work in the grim darkness of the far future!
This is book 10 in the year-long event known as The Beast Arises. There's the obligatory politics, which are great as always, and then to my shock they *actually test the plan!!!* instead of jumping halfassed into battle. The plan works! And you know what that means: the 2nd invasion of Ullanor! (2nd in The War of The Beast, hur hur) Do you like space marines? Because the Deathwatch teams are comprised of space marines from multiple chapters, so we've got all the freaking space marines you'd ever want!
Meanwhile, Zerberyn's Fists Exemplar continue to work with the Iron Warriors. Such delicious H E R E S Y that the galaxy hasn't seen for 1500 years!
Before he died, Vulkan tried to explain the situation to Koorland, and regardless of whether the Lord Commander believed the primarch, he certainly understands the situation now. The ending of the book is shocking. ADB-level shocking. I shouldn't have been so surprised, not after David Guymer's earlier entry in this series, and certainly not after so many amazing character interactions, but hot DAMN. The threads cut here had been woven since the very beginning of the series, and it's an incredibly painful payoff. I love it.