Mordgud “Black-Shoulder” Heylasdottir is a woman on a mission. Well… three missions, actually. The first is to find her grandmother, whose last correspondence was that she was leaving the Skaal village in Solstheim to “join the fight.” The second is to help her friend Thaeril find a way to fight back against the Thalmor, communicating long-distance through a pair of journals. The third is to figure out who the voice in her head is. Upon arriving in Solstheim, however, things start to go very wrong. She loses contact with Thaeril, finds no sign of her grandmother, and gets caught up in a mess between a pirate captain and the mercenary Teldryn Sero. When a new voice joins the one in her head – a voice that takes her over, drops her in strange places, and can absorb the souls of dragons through her body – Mordgud’s mind becomes a battlefield between a protective ancestor and an ancient evil. The question becomes not whether she can beat back the darkness, but whether or not she’ll still be sane on the other side – and who else might know about the Book of Shadows?