Arms-Commander takes place ten years after the end of The Chaos Balance and tells the story of the legendary Saryn. The keep of Westwind, in the cold mountainous heights called the Roof of the World, is facing attack by the adjoining land of Gallos. Arthanos, son and heir to the ailing Prefect of Gallos, wishes to destroy Westwind because the idea of a land where women rule is total anathema to him.

Saryn, Arms-Commander of Westwind, is dispatched to a neighboring land, Lornth, to seek support against the Gallosians. In the background, the trading council of Suthya is secretly and informally allied with Gallos against Westwind and begins to bribe lord-holders in Lornth to foment rebellion and civil war. They hope to create such turmoil in Lornth that the weakened land will fall to Suthya. But Zeldyan, regent of Lornth, has problems in her family. To secure Zeldyan’s aid, Saryn must pledge her personal support—and any Westwind guard forces she can raise—to the defense of Zeldyan and her son. The fate of four lands, including Westwind, rests on Saryn’s actions.