The world is hanging by a thread. Aden has ordered Twist's and Jonas's execution, and fae are on their heals. Now Twist might be the only one who can save his friends and the rest of the world.

It's been a long road. Twist has gone from an unassuming clockmaker to a heroic adventurer and dragon slayer. He's gone from being a lonely orphan to a man with a large and loving family, a dotting fiancee, a friend as dear as a brother. Gone are the days of silence and soot under the London rain, now that Twist spends his days crossing the world with magical beings, off on grand adventures.

Along the way, things have also changed from calm, to dire. Evil fairies want Twist's death, and they will stop at nothing to have it. They have conscripted the Rooks into service, and they are now threatening every single person that Twist holds dear. His friends and family tell him that they will brave the dangers and live the rest of their lives in hiding for his sake, but Twist can't bear to let them all be exiled from their own happiness and freedom.

The only people who still might be able to stop the fae once and for all, freeing Twist and his friends forever, are the mysterious race of clockwork Atlanteans who have been in hiding for a thousand years. Twist, however, happens to have found their hiding place, by accident. They made him promise to keep them secret and to never return, but now has no choice but to break his word and go to ask for their help.