Along with the original Sebastian Michaelis and newly-demonized Ciel Phantomhive, there is to be a new set of characters introduced. A young Princess Abigail meets with Ciel after running away from her family in Russia, being brought over by her double-teamed demon servants. It is said that the young girl had made contracts with a demon butler, Artemis Lokelet, along with a demon maid, Carmella Chrysalis.
Recognizing Sebastian from a meeting during a contract previous to Ciel, Artemis tells Sebastian that there is a possible way to revive Ciel as a human, therefor allowing Sebastian to consume his soul. However, Artemis refuses to speak until he gets one thing that he wants, and cannot do himself due to the contract he has with the Princess: The death of Carmella.
This is part of the plot. I'm so happy that season 3 is coming out May 7, 2014!!!!