In the third of the Castle novels, Steph Swainston takes the reader ever deeper into a world of beauty and terror. . .

The endless war for survival against the merciless Insects has reached yet another stalemate for the Circle, the immortals who serve the Emperor of the Fourlands. The building of a massive dam has driven the Insects back, but it's only a matter of time before they find another way to advance.

Jant, the Emperor's winged Messenger, is called away from battle to find the daughter of fellow immortal, Lightning. Cyan has gone missing in the city of Hacilith, and Lightning wants him to bring her back. But Jant knows better than anyone just how much trouble a teenager can get into in Hacilith's underworld . . .

So begins a hectic quest. A quest that will take Jant back to his past, back to the bizarre world of the Shift and, eventually, back to the Fourlands. Just as it faces a terrifying new threat.