The world of Idos is on the verge of destruction, wracked by catastrophic storms and plagued by ravening tyranids. Into this maelstrom come the Raven Guard 4th Company, the warzone perfectly suited to their lightning-strike methods of combat. Led by Veteran Sergeant Grayvus, their mission is simple to rescue the planets last survivors. Grayvus and his company must fight their way through genestealers and a deadly biomorph if they are to succeed and reclaim Idos for the Imperium.