The Living Stone: To Take a World:

Exhausted, disheartened, and defeated, Baey and her companions have somehow managed to make it to Alkemar.... Now an even more dangerous task looms before them, and an even more dangerous arrangement: they must split up.
Some must go to the heart of Rugo and find The Living Stone, braving a country infested with Skayla's violet-eyed lackeys. And what happens when their best allies seem to be part of the race Baeno has hated for so long?
Meanwhile, Baey and her mentor are left in Alkemar to try and form new alliances, while the former GhostMaker struggles to overcome his past and the memories that now haunt him. Will anyone else be able to look beyond his past and trust them?

About the A Daughter's Ransom series:

The TetraWorlds live in ignorance of each other's existence....
One fallen behind in a Medieval time of fantastic and dangerous creatures, another fallen asleep in the comfort of their Victorian age, and the last torn apart by its own Modern innovation. When a dark threat rises up against them-one so quiet that none know to stop it, a Guard from each world must be called to protect their planet's source. But what will happen when these worlds entwine?