In the canton of Yarrowdale, at the very edge of the Empire's reach, an impossible crime has occurred. A Treasury officer has disappeared into thin air--abducted from his quarters while the door and windows remained locked from the inside, in a building whose entrances and exits are all under constant guard.

To solve the case, the Empire calls on its most brilliant and mercurial investigator, the great Ana Dolabra. At her side, as always, is her bemused assistant Dinios Kol.

Before long, Ana's discovered that they're not investigating a disappearance, but a murder--and that the killing was just the first chess move by an adversary who seems to be able to pass through warded doors like a ghost, and who can predict every one of Ana's moves as though they can see the future.

Worse still, the killer seems to be targeting the high-security compound known as the Shroud. Here, the Empire's greatest minds dissect fallen Titans to harness the volatile magic found in their blood. Should it fall, the destruction would be terrible indeed--and the Empire itself will grind to a halt, robbed of the magic that allows its wheels of power to turn.

Din has seen Ana solve impossible cases before. But this time, with the stakes higher than ever and Ana seemingly a step behind their adversary at every turn, he fears that his superior has finally met an enemy she can't defeat.