Rosie Strange doesn't believe in ghosts or witches or magic. No, not at all. It's no surprise therefore when she inherits the ramshackle Essex Witch Museum, her first thought is to take the money and run.

Still, the museum exerts a curious pull over Rosie. There's the eccentric academic who bustles in to demand she help in a hunt for old bones, those of the notorious Ursula Cadence, a witch long since put to death. And there's curator Sam Stone, a man about whom Rosie can't decide if he's tiresomely annoying or extremely captivating. It all adds up to looking like her plans to sell the museum might need to be delayed, just for a while.

Finding herself and Sam embroiled in a most peculiar centuries-old mystery, Rosie is quickly expelled from her comfort zone, where to her horror, the secrets of the past come with their own real, and all too present, danger as a strange magic threatens to envelope them all.