The Pearl Hunter by Beck

A stunning, Japanese-inspired debut fantasy in the vein of Grace Lin featuring twin pearl divers, in which one sister goes to the ends of the earth to rescue her twin, who's been stolen by a ghost whale.

Kai and Kishi share the same futon, the same face, and the same talent for pearl diving. But Kishi is the obedient daughter, while Kai tries to push boundaries, and sometimes they fight as fiercely as only the closest of twin sisters can. Still, when Kishi is stolen by the legendary ghost whale, nothing will stop Kai from searching deep in the ocean to bring her home.

But such a rescue is beyond the power of an ordinary mortal. Kai strikes a deal with the gods: she’ll steal a magic pearl from faraway Sky Mountain in exchange for her sister’s soul. As she journeys across the treacherous landscape of the Heiwadai Empire, Kai must navigate encounters with scheming bandits, a power-hungry warlord, and a legion of conniving fox spirits, all the while keeping to her mission to save her sister. And when a new friendship becomes something almost as powerful as her love for her twin, Kai must make impossible choices and risk everything just to get home again.

Woven through with Japanese culture and legends, this many-layered story will grip readers of all ages.