City of islands

In the archipelago known as the City of Islands, magic floats through the air as songs. Mara has grown up fascinated by the spell-songs and has longed to become a great song mage. However, after her mentor Bindy, the bone-mage, is killed by a rival, Mara must go work for the powerful Lady of the Tides, from whom she earns her keep by diving into the ocean searching for magic treasures. One day she finds a trove of skeletons of fantastic creatures--winged lizards and horned horses--and in the bones is a powerful spell-song humming. Instead of teaching her the magic, however, the Lady of the Tides forces Mara to go to the island fortress of Winter Blade to find where the song came from.