Commonwealth Universe, Age 3: Volume 5: The Lady and the Order By Michelle Levigne

Vidan was again reaching out to the stars: sadder and wiser...and cautious, unwilling to repeat the mistakes of the ancestors. The Commonwealth was born, reaching out to lost colonies and establishing new ones, rediscovering lost technology and how to navigate the star-ways. Many of the lost colonies not only survived but thrived--and they remembered their abandonment and the harsh centuries of the Downfall...

Bain and Lin meet up with Sister High Scholar Marnya, a member of the Order of Kilvordi--the Church scholars and scientists who brought civilization back from the destruction of the Downfall and returned Humans to space. Marnya asks their help on a very important mission. She needs to travel in disguise, to see if the conditions on the colony worlds match the reports that she receives. Plus, someone's trying to kill members of the Order, and Marnya is the most important target of all. Bain's dreams of having the power and resources to help the helpless come a little closer to reality as he learns from Marnya and her bodyguard, Jax.