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?

About The Series:

The  A Daughter's Ransom Series is an eight book series that spans across the three genres of fantasy, steampunk, and sci-fi. The series will explore three different worlds, each based on one of the genres listed above. The series itself comprises of two trilogies(one of them a fantasy trilogy, the other a steampunk trilogy), a scifi novel, and then a final book that will tie the three worlds together. The publishing schedule has it so that it alternates between the fantasy trilogy(The Exiled) and the steampunk trilogy(To Take a World). Each book is to be released approximately six months apart.