The time has come – if the Imperium is to survive the ork invasion, it must strike at the heart of the greenskin empire. Their home world has been identified, and Koorland, aided by a primarch, leads the assault… The Imperium has been brought to the edge of extinction by an ork invasion of unprecedented scale and depth. Piecemeal strikes against the invaders prove ineffective - for every ork fleet destroyed, five more appear. The only solution is to find and kill the orks' warlord - the Great Beast. Surely if its leader is killed, the greenskins' empire will fall apart in agony of infighting and confusion. Lord Commander Koorland assembles a mighty army, but when they arrives on the orks home world, the forces of the Imperium discover they have disastrously underestimated the might and ingenuity of their enemy. A primarch, the last Imperial Fist and the biggest Imperial army since the Heresy walk into the ork homeworld… but it's no joke. This is the big one, and drama is guaranteed.