Millie, a 42-year-old former graphic designer, and her dog find themselves transported to the realm of Nightshade, a world populated by vampires, ghosts, monsters, and all manner of creatures. Now, Millie's got a new career as a witch, with her dog as her werewolf companion. The two of them, along with Nightshade's own queen Talia, a dullahan with a chip on their shoulder, and a bored drider, are tasked with keeping the realm safe from a horror too eldritch even for Nightshade.