It is M32, a thousand years after the Horus Heresy. The Scouring is over and the Imperium at the height of its post-Crusade power. When Magnus the Red is tracked down to Gangava Prime, the Space Wolves hasten to engage the daemon primarch. Even as Great Wolf Harek Ironhelm closes on his ancient enemy, the Fang on the Space Wolves home world is besieged by a massive force of Thousand Sons. A desperate battle ensues as the skeleton forces of Wolf Lord Asvald Greylock attempt to hold back the attacking hosts before the last of his meagre defences gives in. Though a single Scout ship survives to summon Great Wolf Harek Ironhelm back to Fenris, none of the defenders truly realise the full scale the horror that awaits them, nor what the Battle for the Fang will cost them all.