The grand halls of Fenris grow ever quieter following arduous campaigns. Concerned by his Chapter's diminishing numbers, the Great Wolf Logan Grimnar entrusts Njal Stormcaller to uncover the remedy of their plight. When a 10,000-year-old enemy embeds itself in the Rune Priest's mind, it claims the salvation he seeks lies where it all began. On Prospero. Alongside an eclectic company of injured Space Wolves, Thralls and a Trickster who is more hindrance than help, the Stormcaller sets forth. But it soon becomes apparent that greater mechanisms are at work. It is no longer only the Sons of Russ' fate at stake, but the entire Imperium.