The duo released "Rebels: City of Indra: The Story of Lex and Livia" in 2014 and have been working on a follow up to the dystopian story about two super-powered girls who embark on a journey together, reported Female First.
The new book titled, "Time of the Twins", has been co-written with Elizabeth Killmond-Roman and Katherine Killmond.
Kylie, 18, said, "In our first book, 'Rebels: City of Indra', we left Lex and Livia in a place where their future was uncertain. Now, in Time of the Twins, you'll learn how these sisters struggle to get to know each other and deal with their fate."
