In this spellbinding debut novel, two estranged half-sisters tasked with guarding their family's library of magical books must work together to unravel a deadly secret at the heart of their collection--a tale of familial loyalty and betrayal, and the pursuit of magic and power.

For generations, the Kalotay family has guarded a collection of ancient and rare books. Books that let a person walk through walls or manipulate the elements--books of magic that half-sisters Joanna and Esther have been raised to revere and protect.

All magic comes with a price, though, and for years the sisters have been separated. Esther has fled to a remote base in Antarctica to escape the fate that killed her own mother, and Joanna's isolated herself in their family home in Vermont, devoting her life to the study of these cherished volumes. But after their father dies suddenly while reading a book Joanna has never seen before, the sisters must reunite to preserve their family legacy. In the process, they'll uncover a world of magic far bigger and more dangerous than they ever imagined, and all the secrets their parents kept hidden; secrets that span centuries, continents, and even other libraries . . .

In the great tradition of Ninth House, The Magicians, and Practical Magic, this is a suspenseful and richly atmospheric novel that draws readers into a vast world filled with mystery and magic, romance, and intrigue--and marks the debut of an extraordinary new voice in speculative fiction.