You read the title right...... dont read below the break here if you don't want to be in the know.
via Black Templars on Reddit
- The Chaos invasion is at first overwhelming, but clever use of ceding ground to the orks, genestealers, etc means that Calgar is able to pit his foes against one another and slow them down, at the cost of the planet being less salvageable should they somehow win.
- The Vengeful spirit and accompanying chaos fleet are absolutely decimating the Imperial navy, but it's still not quite enough. As a result Abaddon makes a deal with the Fallen (who are hiding in the swirl, as they have a fortress city in there, hence why the Dark Angels were always looking at it in book 1) and they activate a gravity weapon-esque thing called the voidclaw that messes with all the ships in orbit. The chaos navy knew it was coming and had positioned themselves accordingly, but the Imperials are shredded by it and Chaos now has overwhelming naval superiority.
- Calgar realises that he's stuffed and his promise to Guilliman will be unfulfilled if things keep progressing at this rate, so he hatches a plan. Thing is, he ideally needs some eldar friends if this plan is going to work, so he goes to the angry Saim Hann lot and after fighting his way through to them and surrounding them, manages to hold a successful parlay.
- The plan is basically "Take an aeldari ship, because they're stealthy to avoid radar, and have psykers to avoid the black legion's sorcerers' "psychic radar", fill it with a bunch of deathstrike missiles and ram the vengeful spirit like a fire ship, making Francis Drake proud."
- While this plan is going on, Abaddon and Calgar + their respective bodyguards have their duel. Calgar is trying to draw it out, and this is ok at the start, but eventually the superiority of Abaddon's wargear is really what does it, and Calgar gets sliced open, with his primary heart completely caput and his secondary one with a big dent in it. Just as Abaddon is about to finish him, Haarken gets word that the Vengeful Spirit is in trouble, and Abaddon falls back, which really pisses off his very thirsty sword.
- Sure enough, the plan worked, with the Imperial Navy's remaining ships trying to open up a path for the Aeldari (there's a funny little bit here about how they dragged so many ships for this attack away from other planets that the Necrons, etc just took them) and the Eldar managed to ram the Vengeful spirit, ripping a whopping great big hole in it. The ship is very nearly dead, but manages to pull off an emergency warp translation (and therefore will probably be fixed up and fine by the time the writers need it as a plot device), but this hands naval superiority/equality at least back to the Imperium.
- Calgar survives his grevious wounds, but is no longer able to fight on the front, instead directing everything from his apothecarion bed. Vigilus is still absolutely boned, but it's not quite over yet.
That's all folks!