Warhammer 40k - Horus Heresy Audiobook - Galaxy in Flames by Ben Counter

THE STORY
Having recovered from his grievous injuries, Warmaster Horus leads the triumphant Imperial forces against the rebel world of Isstvan III. Though the rebels are swiftly crushed, Horus's treachery is finally revealed when the planet is razed by virus bombs and Space Marines turn on their battle-brothers in the most bitter struggle imaginable.

LISTEN TO IT BECAUSE...
This is the third novel in the epic opening trilogy of the Horus Heresy. In Galaxy in Flames, the Warmaster’s treachery is revealed as he seeks to purge those warriors still loyal to the Emperor from the ranks of his Legion.
The battle for the soul of mankind has truly begun.