The Forsaken Isles are on the brink of revolution. Three individuals are about to push it over the edge and trigger events that will lead to a final showdown between ancient forces and the new overlords of the land. Spaeth Dobrin is destined to life as a ritual healer - but as the dhotamar of the tiny, isolated island of Yora, she will be caught in a perpetual bond between herself and the people she has cured. Is it slavery, or is it love? Meanwhile, Harg, the troubled and rebellious veteran, returns to find his home transformed by conquest. And Nathaway, the well-intentioned imperialist, arrives to teach Spaeth's people "civilization," only to become an explorer in the strange realm of the Forsakens. These two men will propel Spaeth into a vortex of war, temptation, and - just possibly - freedom!

Revolution has broken out in the Forsaken Isles. The islanders have risen up to drive out the Inning Empire, but still they have no one to unite them. Only an Ison can do that - a leader whose heart has been cleansed by the curing of dhota-nur. The power to create an Ison lies in the hands of three people, and none of them are heroes. Spaeth has the ancient Lashnura heritage, but does she have the stature? Harg has the military genius, but he utterly rejects the price of dhota-nur. And Nathaway, the Inning outsider, finds himself unexpectedly holding the key to the future of the Isles. Perilously poised between Inning conquest and the savage powers of ancient forces, the Forsakens need them to decide. But for an Ison to rise, each of them must betray one of the others. Ison of the Isles continues the story started in Isles of the Forsaken.