Sarah Buhrman 
Carrier [EPUB ebook] 

To combat over-population, humanity has condensed itself. Now, there are carriers, people who host 12 other consciousnesses, riders, along with their own. When one of Kat’s riders is convicted of a heinous crime and condemned to death, all 13 of them are sentenced together.

Kat must flee for her life and search out the truth with the help of the whispers, dreams and visions that her riders give her. But the secrets could bring down some of the most powerful of the Council, and they will protect their sovereignty.