Pale Queen Rising (Pale Queen Series Book 1) by A. R. Kahler
As the royal assassin, Claire is used to moving between the mortal world and the Winter Kingdom. When the queen commands her to kill, Claire does the job and doesn’t ask questions. Her deadly skills and loyalty are soon tested when Claire is sent to the Immortal Circus, one of the many places where “Dream” is harvested from the imaginings of mortals. There she must find the culprit who is causing Dream to mysteriously disappear before the Winter Kingdom’s supply is depleted enough to threaten its very survival. But when she meets Roxie, a beautiful mortal singer with a strange link to the Dream thieves, Claire quickly recognizes an odd and unexplained connection that may cloud her judgment. As each new clue unveils another secret, Claire finds herself confronting the riddle of her own buried past—and a dangerous illusion that, as part of the Immortal Circus, is just another act in the show.