Hevun's Ambassador is the second novel in the Hevun's Child trilogy and can be purchased here.
C.M. Weller took great delight in making hir readers wait to see if Sahra is alive, and thus, it's quite a few pages before we see our heroine, and more before she's mentioned by name.
The book opens with Captain Wapun and her science vessel finding a small life-pod with intermittent life signs, according to Murphy's Law. Inside the tiny craft are what appears to be two small children. One cyanotic and one bruised.
Sahra spends the majority of her time with these strangers in utter paranoia. She can't conceive of completely free humans and resorts to various levels of subterfuge before she allows a very shaky trust. It's during this process that her friend Simy is revealed as none other than the station boogey-man, Eon.
Then the oddities of Galactic Law appoint her Ambassador for Hevun. Negotiations and official channels work much quicker in this future than they do in reality, and the Galactic Alliance agrees to help Sahra free her fellow humans from the Tu'att's hold; as well as freeing the other planets in the Tu'att empire.
Sahra displays her strategic genius by providing simulations of how to use the Galactic ships and Simy provides the tactics preferred by the Tu'att. Together, they make a near-unstoppable team.
Sahra and her new allies find an abandoned station, apparently run by a string-runner who got hir personal math wrong. They use this station as a temporary beach-head while the allies come through, and while Sahra contacts the rebels.
With the rebels' local intelligence, a series of 'miracles' are engineered, including the vanishing of all the stations' humans. The final scene features Sahra facing down the Majestrix, apparently alone and unarmed, before revealing that there is an army in the walls and this is the ultimate manouvree in a coup.
...which leads us into Hevun's Gate.