Publisher’s blurb for Paul S. Kemp’s next Star Wars novel, Star Wars: Lords of the Sith:
When the Emperor and his notorious apprentice, Darth Vader, find themselves stranded in the middle of insurgent action on an inhospitable planet, they must rely solely on each other, the Force, and their awesome martial skills to prevail. Created in collaboration with the Lucasfilm Story Group. Coming March 2015. Jacket art by Aaron McBride.
Kemp goes on to say in his blog post that:
I can say a few things more about the book: First, as is apparent from that spectacular cover, the book features Vader and Palpatine. It also features a character who I’m not allowed to name just yet, but who appeared in The Clone Wars animated series. In terms of where it fits in the timeline, Lords of the Sith is set after the Revenge of the Sith film and before the forthcoming Rebels television show.
Given Kemp’s ability to tell dark stories featuring anti-heroes and copious amounts of gore I am rather excited.
Source: Paulskemp.com