You should have asked if it was pre Horus Heresy.
That sounds like the whole "rushing to warn him about Horus" event. I read a summary of that; have the books sitting on my harddrive somewhere; haven't felt the desire to read them.
Most of the 40K novels I've read have been shit. Like the ones about the Grey Knight that defeats demon princes with the power of FRIENDSHIP AND IMAGINATION. :| No shit. And the action sequences read like a little kid mashing action figures together while screaming "PEW PEW PEW KABOOM PEW PEW!!!".
Or Gaunt's Ghosts, with the emo regiment of "super stealthy snipers", who are used as heavy infantry by the functionally retarded leaders of the crusade, apparently to make Gaunt, a decisively mediocre character, seem great by comparison, and to fabricate a further plight for the fucks, so they get to be the little guys that win everything, and suffer the most, but get no credit, so they can mope about it some more. >:|
Faith and Fire is the most horrendous piece of shit I've ever read to completion, and only then because it was short and became a bit more entertaining when everyone stopped talking so fucking much and started dying. The dialog was some of the most awkward, unnatural drivel I've ever seen. And even at the end, after it's partially redeemed itself, the author fucks it up by not having the central characters die. One of them climbs a fucking cliff in fused, unpowered power armor, hijacks a helicopter, flies it into the mouth of an active volcano full of demons, in order to save her
girlfriend squad. I mean jesus fucking shit, the most sympathetic character was the fucking villain (the witch, not the priest)...
The Ciaphas Cain books were great. And I believe non-canon in that the central figures aren't batshit insane imbeciles, and that the IG uses tactics more appropriate to, you know, the technology they have. Actual guns, and tanks, and planes, and whatnot. Rather than the primitive, WWI-esque bullshit that appears to be more canon.