The Crimson Fortress (The Ivory Key Duology, Bk. 2)

Their missions force them to split up and disperse across Ashoka and beyond. When a rash decision by the council strips Vira of her power, her journey to reclaim her throne takes on new meaning. Kaleb travels to the neighboring country of Lyria to uncover its emperor's motives and beets a prince seeking answers of his own. Ronak's efforts to escape his arranged marriage and exonerate his brother lead to a series of risky deals that only bring him closer to what he's running from. And Riya's newfound power had turned unpredictable, but her search for answers only raises more questions.

when their attempts at decoding the key release an ancient power, the siblings must align to face the past and save their future once and for all. In a quest that culminates in a deadly labyrinth, there's only one way they will succeed: together.