Quill is an outcast, an exiled Hesperian navigator hired to find a "fallen star." Petal and Junk are feral children, drifting across the open ocean, where every day is a struggle for survival.
After Quill's crew betrays her and Petal's sister is kidnapped by a Hesperian warship, both girls team up on an island-hopping odyssey across the water world of Ea to recover what they've lost.
Hounded by pirates, imprisoned by cannibals, and chased by shadowy Hesperian forces, the girls quickly find themselves kingmakers in the great war between land and sea.