It's in Codex: Space Marines- basically a gigantic necron construct, we're talking small moon sized, called the World Engine starts destroying Imperial Planets so over a dozen Chapters and battlefleets of the Imperial Navy confront it and essentially get their arses handed to them because none of their weapons can penetrate it's shields. Until the Chapter Master of the Astral Knights decides to use his Battle Barge as an awesome torpedo and as the prow of the Barge shorts out the shield for a moment the entire chapter descends to the World Engine's surface in drop pods and gunships.
For 100 hours the Astral Knights managed to rampage throughout the World Engine, destroying whatever they could whilst trying to stay ahead of the tens of thousands of Necrons, they all die but in his last moment the Chapter Master finally destroys a relay that when added to all the damage they've already achieved sends the shields and a large number of the weapons offline- the Imperials just blast the fuck out of it with cyclonic torpedos (i.e world enders) then, destroying it and towing the remains of the Astral Knight's Barge to the surface of Safehold, the last planet the Necrons killed, where they set up a cemetary for each and every Astral Knight that sacrificed himself.
Now each of the other 12 Chapters who participated in the conflict sends warriors so that there is always 20 Astartes present on Safehold to honour the dead and keep scavengers away.
think i should give these a read after ive finished the books im in the middle of reading atm, any thoughts on which is the best read to start with or would you suggest personal preference in terms of chapters written about up to now?
