To establish goodwill throughout the kingdom, Queen Rose embarks on a royal tour where she unexpectedly discovers why the Restless Sands are erupting, while her twin sister, Queen Wren, journeys to the icy north to bargain for their grandmother's freedom.

Twin queens Wren and Rose have claimed their crowns . . . but not everyone is happy about witches sitting on Eana's throne. Cool-headed Rose sets off on a Royal Tour to win over the doubters, but soon finds herself drawn to the Sunless Kingdom. Here secrets are revealed about those closest to her, and Rose finds her loyalties divided. Meanwhile rebellious Wren steals away to the icy north to rescue their beloved grandmother, Banba. But when she accepts King Alarik's deadly magical bargain in exchange for Banba's freedom, the spell has unexpected - and far-reaching - consequences . . . As an ancient curse begins to arise from the darkness, the sisters must come together and unite the crown. Their lives - and the future of Eana - depend on it.