The book starts with the capture of the main character by chaos forces (Ultramarines Omnibus copy?) but this time, filling with gladiator-like chaos arenas where he will fight hellspawns and mutants.
And so it goes most of the book, which is a pity because could almost be any other non-grey knight character. It is just "remembered" here and there with small details, but quite hollow in general. Excepting two or three specific points, the whole book could have any other main character without anybody noticing it.
In fact this way of forced refering to previous books characters and enemies is done too much, as if the author was trying to force us to link with the past because the current one was too detached (and indeed it is).
The story (without spoilers) gets really really absurd, to some points that I doubt a Grey Knight would have gone.
Also, unlike in other books not part of this trilogy Grey Knights are usually treated not as powerfull as here... but in this book it is too extreme. Way too much easy killing of demons and monsters by an almost unarmed GK (no power armor, no halberd, just gladiator old weapons).
A big dissapointment. I just finished it to close the trilogy.