After the horrors of the Dropsite Massacre, the Raven Guard are trying to survive in the caves and mountains of Isstvan V. Their plight is desperate, and escape from the roaming Chaos Legions seems impossible. Meanwhile Colonel Valerius of the Imperial army begins suffering terrible dreams, believing the Raven Guard to be in trouble. But he faces obstacles of his own in attempting what he believes will be a heroic rescue. Can the decimated Legion hold out against the forces of the World Eaters long enough to reach an unlikely salvation?