Mélusine—a city of secrets and lies, pleasure and pain, magic and corruption—and destinies lost and found. Felix Harrowgate is a dashing, highly respected wizard. But his aristocratic peers don't know his dark past—how his abusive former master enslaved him, body and soul, and trained him to pass as a nobleman. Within the walls of the Mirador—Melusine's citadel of power and wizardry—Felix believed he was safe. He was wrong. Now, the horrors of his previous life have found him and threaten to destroy all he has since become. Mildmay the Fox is used to being hunted. Raised as a kept-thief and trained as an assassin, he escaped his Keeper long ago and lives on his own as a cat burglar. But now he has been caught by a mysterious foreign wizard using a powerful calling charm. And yet the wizard was looking not for Mildmay—but for Felix Harrowgate. Thrown together by fate, the broken wizard Felix and the wanted killer Mildmay journey far from Melusine through lands thick with strange magics and terrible demons of darkness. But it is the shocking secret from their pasts, linking them inexorably together, that will either save them, or destroy them.

Felix Harrowgate was a dashing and powerful wizard until his former master wrenched Felix’s magic from him and used it to shatter the Virtu—the orb that is the keystone for the protection and magic of the wizards of the city. Felix has painfully clawed his way back to sanity, and his only chance to reclaim the life he once knew is to repair the seemingly irreparable—to restore the Virtu. Mildmay the Fox was an assassin and a cat-burglar—until a curse caught up with him and his life changed forever. Haunted by death, his leg damaged by the curse that should have killed him, he does not know what awaits him in Mélusine, but for good or ill, his fate is tied to Felix’s, by blood…and by magic. On their journey, Felix and Mildmay will encounter friends and enemies old and new, vengeful spirits and ancient goddesses. They will uncover secrets better left buried. But nothing can prepare them for what awaits their return: Felix’s former master, the cruel and decadent wizard Malker Gennadion…

In a continuation of the series that began with MÉlusine and The Virtu, wizard Felix Harrowgate returns to the Mirador, the citadel of power and wizardry, unaware that enemies from the Bastion, a rival school of wizards, plan to use him to destroy the Mirador, unless Felix's half-brother, Mildmay the Fox, can stop them.

In the spellbinding conclusion to the brilliant fantasy series, Doctrine of Labyrinths, two brothers discover their ultimate destiny. Exiled from Melusine for the crime of heresy, Felix Harrowgate and his half-brother Mildmay journey to the land of Corambis to face judgement from a ruling body of wizards. Both brothers carry memories, regret, and-hidden deep in their hearts-hope.