- "All is dust..."
- —Book's tag-line
A Thousand Sons is the twelfth volume in the Horus Heresy series of novels.
Censured at the Council of Nikea for his flagrant use of sorcery, Magnus the Red and his Thousand Sons Legion retreat to their homeworld of Prospero to continue their use of the arcane arts in secret. But when the ill-fated Primarch foresees the treachery of Warmaster Horus and warns the Emperor with the very powers he was forbidden to use, the Master of Mankind dispatches fellow Primarch Leman Russ to attack Prospero itself. But Magnus has seen more than the betrayal of Horus and the witnessed revelations will change the fate of his fallen Legion, and its Primarch, forever.
A Thousand Sons is the story of Magnus the Red and the Thousand Sons Legion of Space Marines, and for the most part takes place before the Heresy begins. Following a reprimand by the Emperor of Mankind for dabbling in psychic sorcery, Magnus and his Legion secretly continue to study sorcery despite being forbidden to do so. Magnus learns through sorcery of his brother Horus' impending betrayal, and tries, again through sorcery, to warn the Emperor hoping the news would justify his disobedience. However, Magnus overreaches with his powers and causes damage to a vital and secret project the Emperor was undertaking, endangering the safety of Terra itself in the process. The Emperor is enraged and orders Leman Russ and his Space Wolves Legion, accompanied by other Imperial forces, to bring Magnus and his Legion to Terra to account for themselves.
- A Thousand Sons (Novel) by Graham McNeill