Once, Sancia Grado was just a thief with a grudge and a rare talent. Then she learned how to use that talent, and beat the great merchant houses of Tevanne at their own game. With Clef and Berenice, she even saw off an immortal hierophant - but the war they're fighting now is one they know they can't win.

This time, they're not facing robber-baron elites or an immortal hierophant, but an entity whose intelligence is spread over half the globe: a ghost in the machine using the magic of scriving to possess and control not just objects, but human minds.

Despite all their efforts their enemy marches on, implacable, unstoppable - and it's closing in on its true prize: an ancient doorway that leads to the centre of creation itself.

Sancia and her friends glimpse a last desperate opportunity to stop this unbeatable foe - but to do so, they'll have to unlock the centuries-old mystery of scriving's origins and pull off the most daring heist they've ever attempted.

And as if that weren't enough, their adversary might just have a spy in their ranks - and a last trick up its sleeve . . .