London, 1923. Newly minted research assistant Saffron Everleigh is the first woman to hold the position at University College of London. When she attends a dinner party for the school, she expects to engage in conversations about the university's large expedition to the Amazon. What she doesn’t expect is for Mrs. Henry, one of the professors’ wives, to drop to the floor, poisoned by an unknown toxin. Dr. Maxwell, Saffron’s mentor, is the main suspect, and evidence quickly mounts.

When Finlay Ashowan joins the staff of the King and Queen of Daxaria, he’s an enigma. No one knows where he comes from or how he came to be where he is, which suits Fin just fine. He’s satisfied simply serving as the royal cook, keeping nosy passersby out of his kitchen, and concocting some truly uncanny meals. But Fin’s secret identity doesn’t stay hidden for long. After all, it’s not every day a house witch and his kitten familiar, Kraken, take to meddling in imperial affairs.

Librarian Sylvia Ashe knows nothing about her past, having grown up without a father and a mother who refused to discuss him. When she stumbles upon a diary that suggests she's descended from magicians, she's skeptical. After all, magicians are special, and she's just an ordinary woman who loves books. She seeks answers from a member of the most prominent family of magicians, but she quickly learns that finding the truth won't be easy, especially when he turns out to be as artless as her, and more compelling and dangerous than books.

Oddny and Gunnhild meet as children in tenth century Norway, and they could not be more different: Oddny hopes for a quiet life, while Gunnhild burns for power and longs to escape her cruel mother. But after a visiting wisewoman makes an ominous prophecy that involves Oddny, her sister Signy, and Gunnhild, the three girls take a blood oath to help one another always. When Oddny’s farm is destroyed and Signy is kidnapped by Viking raiders, Oddny is set adrift from the life she imagined—but she's determined to save her sister no matter the cost.

Thirty-eight year old Cassandra is lost, alone, and grieving. Her much loved grandmother, Nell, has just died and Cassandra, her life already shaken by a tragic accident 10 years ago, feels like she has lost everything known and dear to her.