A steerswoman must answer any question you ask; her role is to collect knowledge as she travels and to share that knowledge. Steerswomen must always answer truthfully. A valuable and respected asset to the countries they travel, steerswomen are explorers, scientists, and cartographers, dedicated to their order and the accumulation of and preservation of knowledge.
As the steerswomen must answer any question asked of them (as far as their knowledge extends), the other side of the coin is that any question a steerswoman asks must also be answered truthfully. If you refuse to answer or if you lie, you will never gain another answer from a steerswoman, at any time, regardless of the import.
Rowan is a steerswoman who has become interested in some strange jewels. In her efforts to discover their origin, she has a chance meeting at an Inn with an Outskirter warrior who has some of the same jewels in her belt. The two decide to proceed together, but something about Rowan's curiosity about the jewels results in repeated attempts on her life. She and Bel, the Outskirter warrior, are both capable of defending themselves, but the odds against them grow greater.
In their journey to discover more about the jewels (and why their quest has aroused such repeated attempts on their lives), they are joined by a young boy who wants to become a wizard. Initially distrustful, the two women allow him to remain with them for at least a portion of their travels.
The novel has aspects of science fiction, but is essentially a fantasy novel that pits science against magic. I thoroughly enjoyed it and look forward to the next one, The Outskirter's Secret.
You might be interested in this review of the series by Jo Walton.
SF (Walton uses this designation for science fiction/fantasy novels). Originally published in 1989. 288 pages.