Helsreach tells the story of Black Templars Reclusiarch, Grimaldus and his dispatch to lead a crusade to save the hive city of Helsreach in the third war for Armageddon. Grimaldus and company arrive shortly before Armageddon is besieged my the most massive force of Orks in Imperial History. Whilst many of the Templars fight for glory in the void battles and ship to ship combat in the system, Grimaldus is sent to the planet's surface in order to defend Helsreach. The number of enemies involved make this a suicide mission. Grimaldus knows he will die here.
From here the book delves into the month long siege of Helsreach. There are several key points, such as the battle at the docks, that stand out and would be fantastic to recreate on the tabletop. The Space Marine Battles novels are now known for show stoppers like this, and they're what I now look for when reading through them. Where the pace of the book stumbles is in between each of these moments. The characters seem directionless and none of the multiple plot lines seem to go anywhere. They stagnate through most of the book.
It's my opinion that Mr. Dembski-Bowden's weakness is working within the constraints of well defined events within the 40k universe. Much of the background for the battles on Armageddon have been explored in many other books, and indeed the game materials! I feel this hems in what he could have done with the story creatively.
All of this aside, however, there's still a great story told with many fascinating and entertaining characters. When Grimaldus challenges a Titan's Princeps, wades into an ocean of Orks, and finally discerns his purpose in the war, the book hits it's stride and is a blast to read. The conclusion, while short, also does a marvelous job of tying up all of the threads of the story as well. I'd reccommend the book and would give it a 4 out of 5 if I had to score it. The only way it falters is compared to AD-B's other works.
Helsreach is a Space Marine Battles novel. You can find it at Black Library in book or ebook form, or at your local bookstore.