This is book number 3 in the Gilded series.
Jae Hwa Lee spent her sixteenth year in Seoul, trying to destroy the evil immortals who had been torturing her family for centuries. The last thing she expected was to be forced to become their assassin. Trapped in the darkest part of the Spirit World as a servant to the Korean god Kud, fighting to keep her humanity, and unable to contact her loved ones, Jae Hwa is slowly losing hope. Kud, god of darkness, will do anything to keep her as a pawn in his quest for power over all of Korea, her entire family thinks she's dead, and Jae's true love, Marc, believes she is lost to him forever.
When Kud sends Jae to find and steal the powerful Black Turtle orb, Jae sees an opportunity to break free and defeat Kud once and for all...but first she needs to regain Marc's trust and work with him to vanquish the darkness that threatens to overwhelm Korea. There's much to lose as Jae struggles to save the land she's come to call home.