Boucher's World: Transformation

Jade Lowry, the co-discoverer of the way out of the continent-covering Dome of Boucher's World, was kidnapped but managed to escape with the help of her soul-mate, Kendis Rost, and the doomed precog, S'tella.
During the event, she and Kendis discover inexplicable differences about themselves as they go to the aid of their friends who are fighting with the minions of her kidnapper.
Once she and Kendis get back to her home in Village Twelve, what does Lark, the Elwist Healer, and Sparrow, its precog vow-mate have to tell them that explain why they appear to be transforming into something that isn't quite Human?